WorldWideScience

Sample records for underwater research vessel

  1. Integrating Multiple Autonomous Underwater Vessels, Surface Vessels and Aircraft into Oceanographic Research Vessel Operations

    Science.gov (United States)

    McGillivary, P. A.; Borges de Sousa, J.; Martins, R.; Rajan, K.

    2012-12-01

    Autonomous platforms are increasingly used as components of Integrated Ocean Observing Systems and oceanographic research cruises. Systems deployed can include gliders or propeller-driven autonomous underwater vessels (AUVs), autonomous surface vessels (ASVs), and unmanned aircraft systems (UAS). Prior field campaigns have demonstrated successful communication, sensor data fusion and visualization for studies using gliders and AUVs. However, additional requirements exist for incorporating ASVs and UASs into ship operations. For these systems to be optimally integrated into research vessel data management and operational planning systems involves addressing three key issues: real-time field data availability, platform coordination, and data archiving for later analysis. A fleet of AUVs, ASVs and UAS deployed from a research vessel is best operated as a system integrated with the ship, provided communications among them can be sustained. For this purpose, Disruptive Tolerant Networking (DTN) software protocols for operation in communication-challenged environments help ensure reliable high-bandwidth communications. Additionally, system components need to have considerable onboard autonomy, namely adaptive sampling capabilities using their own onboard sensor data stream analysis. We discuss Oceanographic Decision Support System (ODSS) software currently used for situational awareness and planning onshore, and in the near future event detection and response will be coordinated among multiple vehicles. Results from recent field studies from oceanographic research vessels using AUVs, ASVs and UAS, including the Rapid Environmental Picture (REP-12) cruise, are presented describing methods and results for use of multi-vehicle communication and deliberative control networks, adaptive sampling with single and multiple platforms, issues relating to data management and archiving, and finally challenges that remain in addressing these technological issues. Significantly, the

  2. Research vessels

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, P.S.

    The role of the research vessels as a tool for marine research and exploration is very important. Technical requirements of a suitable vessel and the laboratories needed on board are discussed. The history and the research work carried out...

  3. Underwater television camera for monitoring inner side of pressure vessel

    International Nuclear Information System (INIS)

    Takayama, Kazuhiko.

    1997-01-01

    An underwater television support device equipped with a rotatable and vertically movable underwater television camera and an underwater television camera controlling device for monitoring images of the inside of the reactor core photographed by the underwater television camera to control the position of the underwater television camera and the underwater light are disposed on an upper lattice plate of a reactor pressure vessel. Both of them are electrically connected with each other by way of a cable to rapidly observe the inside of the reactor core by the underwater television camera. The reproducibility is extremely satisfactory by efficiently concentrating the position of the camera and image information upon inspection and observation. As a result, the steps for periodical inspection can be reduced to shorten the days for the periodical inspection. Since there is no requirement to withdraw fuel assemblies over a wide reactor core region, and the device can be used with the fuel assemblies being left as they are in the reactor, it is suitable for inspection of detectors for nuclear instrumentation. (N.H.)

  4. Underwater Shock Response Analysis of a Floating Vessel

    Directory of Open Access Journals (Sweden)

    J.E. van Aanhold

    1998-01-01

    Full Text Available The response of a surface vessel to underwater shock has been calculated using an explicit finite element analysis. The analysis model is two-dimensional and contains the floating steel structure, a large surrounding water volume and the free surface. The underwater shock is applied in the form of a plane shock wave and cavitation is considered in the analysis. Advanced computer graphics, in particular video animations, provide a powerful and indispensable means for the presentation and evaluation of the analysis results.

  5. Feasibility of underwater welding of highly irradiated in-vessel components of boiling-water reactors: A literature review

    International Nuclear Information System (INIS)

    Lund, A.L.

    1997-11-01

    In February 1997, the U.S. Nuclear Regulatory Commission (NRC), Office of Nuclear Regulatory Research (RES), initiated a literature review to assess the state of underwater welding technology. In particular, the objective of this literature review was to evaluate the viability of underwater welding in-vessel components of boiling water reactor (BWR) in-vessel components, especially those components fabricated from stainless steels that are subjected to high neutron fluences. This assessment was requested because of the recent increased level of activity in the commercial nuclear industry to address generic issues concerning the reactor vessel and internals, especially those issues related to repair options. This literature review revealed a preponderance of general information about underwater welding technology, as a result of the active research in this field sponsored by the U.S. Navy and offshore oil and gas industry concerns. However, the literature search yielded only a limited amount of information about underwater welding of components in low-fluence areas of BWR in-vessel environments, and no information at all concerning underwater welding experiences in high-fluence environments. Research reported by the staff of the U.S. Department of Energy (DOE) Savannah River Site and researchers from the DOE fusion reactor program proved more fruitful. This research documented relevant experience concerning welding of stainless steel materials in air environments exposed to high neutron fluences. It also addressed problems with welding highly irradiated materials, and primarily attributed those problems to helium-induced cracking in the material. (Helium is produced from the neutron irradiation of boron, an impurity, and nickel.) The researchers found that the amount of helium-induced cracking could be controlled, or even eliminated, by reducing the heat input into the weld and applying a compressive stress perpendicular to the weld path

  6. Pressure vessel made by free forming using underwater explosion

    Directory of Open Access Journals (Sweden)

    H Iyama

    2016-03-01

    Full Text Available Explosive forming is one particular forming technique, in which, mostcommonly, water is used as the pressure transmission medium. In recentyears, we have done the development of the method which obtains anecessary form of the metal by the control of underwater shock wave actson the metal plate, without a metal die. On the other hand, the pressurevessel is required in various fields, but we think that the free forming usingthe underwater shock wave is advantageous in the production of pressurevessel of a simple spherical, ellipse, parabola shape. In this paper, we willintroduce an experiment and several numerical simulations that we carriedout for this technical development.

  7. Ocean Research Enabled by Underwater Gliders.

    Science.gov (United States)

    Rudnick, Daniel L

    2016-01-01

    Underwater gliders are autonomous underwater vehicles that profile vertically by changing their buoyancy and use wings to move horizontally. Gliders are useful for sustained observation at relatively fine horizontal scales, especially to connect the coastal and open ocean. In this review, research topics are grouped by time and length scales. Large-scale topics addressed include the eastern and western boundary currents and the regional effects of climate variability. The accessibility of horizontal length scales of order 1 km allows investigation of mesoscale and submesoscale features such as fronts and eddies. Because the submesoscales dominate vertical fluxes in the ocean, gliders have found application in studies of biogeochemical processes. At the finest scales, gliders have been used to measure internal waves and turbulent dissipation. The review summarizes gliders' achievements to date and assesses their future in ocean observation.

  8. Research on Operational Aspects of Large Autonomous Underwater Glider Fleets

    National Research Council Canada - National Science Library

    Fratantoni, David M

    2007-01-01

    This program supported research on the operational and management issues stemming from application of large fleets of autonomous underwater gliders to oceanographic research and rapid environmental...

  9. Comparing autonomous underwater vehicle (AUV) and vessel-based tracking performance for locating acoustically tagged fish

    OpenAIRE

    Eiler, John H.; Grothues, Thomas M.; Dobarro, Joseph A.; Masuda, Michele M.

    2013-01-01

    Autonomous underwater vehicles (AUV’s) are increasingly used to collect physical, chemical, and biological information in the marine environment. Recent efforts include merging AUV technology with acoustic telemetry to provide information on the distribution and movements of marine fish. We compared surface vessel and AUV tracking capabilities under rigorous conditions in coastal waters near Juneau, Alaska. Tracking surveys were conducted with a REMUS 100 AUV equipped with an integrated acous...

  10. Underwater laser beam welding technology for reactor vessel nozzles of PWRs

    International Nuclear Information System (INIS)

    Yoda, Masaki; Tamura, Masataka; Tamura, Masataka

    2010-01-01

    Toshiba has developed an underwater laser beam welding technology for the maintenance of reactor vessel nozzles of pressurized water reactors (PWRs), which eliminates the need for the drainage of water from the reactor vessel. The new welding system makes it possible to both reduce the work period and minimize the radiation exposure of workers compared with conventional technologies for welding in ambient air. We have confirmed the effectiveness of this technology through experiments in which stress corrosion cracking (SCC) was mitigated on the inner surfaces of nozzles. We are promoting its practical application in Japan and overseas in cooperation with Westinghouse Electric Company, a group company of Toshiba. (author)

  11. Impact of Vessel Noise on Oyster Toadfish (Opsanus tau) Behavior and Implications for Underwater Noise Management

    Science.gov (United States)

    Krahforst, Cecilia S.

    Underwater noise and its impacts on marine life are growing management concerns. This dissertation considers both the ecological and social concerns of underwater noise, using the oyster toadfish (Opsanus tau) as a model species. Oyster toadfish call for mates using a boatwhistle sound, but increased ambient noise levels from vessels or other anthropogenic activities are likely to influence the ability of males to find mates. If increased ambient noise levels reduce fish fitness then underwater noise can impact socially valued ecosystem services (e.g. fisheries). The following ecological objectives of the impacts of underwater noise on oyster toadfish were investigated: (1) to determine how noise influences male calling behavior; (2) to assess how areas of high vessel activity ("noisy") and low vessel activity ("quiet") influence habitat utilization (fish standard length and occupancy rate); and (3) to discover if fitness (number of clutches and number of embryos per clutch) is lower in "noisy" compared with "quiet" sites. Field experiments were executed in "noisy" and "quiet" areas. Recorded calls by males in response to playback sounds (vessel, predator, and snapping shrimp sounds) and egg deposition by females ("noisy" vs. "quiet" sites) demonstrated that oyster toadfish are impacted by underwater noise. First, males decreased their call rates and called louder in response to increased ambient noise levels. Second, oyster toadfish selected nesting sites in areas with little or no inboard motorboat activity. Third, male oyster toadfish at "noisy" sites either had no egg clutches on their shelters or the number of embryos per clutch was significantly lower than in the "quiet" areas. Underwater noise and disturbance from vessels are influencing the fitness of the oyster toadfish. The social significance of the growing concerns regarding underwater noise was investigated by identifying dominant themes found within two types of texts: four recent underwater noise

  12. Underwater cutting of stainless steel plate and pipe for dismantling reactor pressure vessels

    International Nuclear Information System (INIS)

    Hamasaki, M.; Tateiwa, F.; Kanatani, F.; Yamashita, S.

    1982-01-01

    A consumable electrode water jet cutting technique is described. Satisfactory underwater cutting of 80mm stainless steel plate using a current of 2000A and at a water depth of 200mm has been demonstrated. The electrical requirements for this arc welding method applied to cutting were found to be approximately one third those required for conventional plasma arc cutting for the same thickness plate. An application of this technique might be found in the dismantling of atomic reactor pressure vessels, and parts of commercial atomic reactors. (author)

  13. Underwater sound from vessel traffic reduces the effective communication range in Atlantic cod and haddock.

    Science.gov (United States)

    Stanley, Jenni A; Van Parijs, Sofie M; Hatch, Leila T

    2017-11-07

    Stellwagen Bank National Marine Sanctuary is located in Massachusetts Bay off the densely populated northeast coast of the United States; subsequently, the marine inhabitants of the area are exposed to elevated levels of anthropogenic underwater sound, particularly due to commercial shipping. The current study investigated the alteration of estimated effective communication spaces at three spawning locations for populations of the commercially and ecologically important fishes, Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus). Both the ambient sound pressure levels and the estimated effective vocalization radii, estimated through spherical spreading models, fluctuated dramatically during the three-month recording periods. Increases in sound pressure level appeared to be largely driven by large vessel activity, and accordingly exhibited a significant positive correlation with the number of Automatic Identification System tracked vessels at the two of the three sites. The near constant high levels of low frequency sound and consequential reduction in the communication space observed at these recording sites during times of high vocalization activity raises significant concerns that communication between conspecifics may be compromised during critical biological periods. This study takes the first steps in evaluating these animals' communication spaces and alteration of these spaces due to anthropogenic underwater sound.

  14. Underwater Shock Wave Research Applied to Therapeutic Device Developments

    Science.gov (United States)

    Takayama, K.; Yamamoto, H.; Shimokawa, H.

    2013-07-01

    The chronological development of underwater shock wave research performed at the Shock Wave Research Center of the Institute of Fluid Science at the Tohoku University is presented. Firstly, the generation of planar underwater shock waves in shock tubes and their visualization by using the conventional shadowgraph and schlieren methods are described. Secondly, the generation of spherical underwater shock waves by exploding lead azide pellets weighing from several tens of micrograms to 100 mg, that were ignited by irradiating with a Q-switched laser beam, and their visualization by using double exposure holographic interferometry are presented. The initiation, propagation, reflection, focusing of underwater shock waves, and their interaction with various interfaces, in particular, with air bubbles, are visualized quantitatively. Based on such a fundamental underwater shock wave research, collaboration with the School of Medicine at the Tohoku University was started for developing a shock wave assisted therapeutic device, which was named an extracorporeal shock wave lithotripter (ESWL). Miniature shock waves created by irradiation with Q-switched HO:YAG laser beams are studied, as applied to damaged dysfunctional nerve cells in the myocardium in a precisely controlled manner, and are effectively used to design a catheter for treating arrhythmia.

  15. The Research of Optical Turbulence Model in Underwater Imaging System

    Directory of Open Access Journals (Sweden)

    Liying Sun

    2014-01-01

    Full Text Available In order to research the effect of turbulence on underwater imaging system and image restoration, the underwater turbulence model is simulated by computer fluid dynamics. This model is obtained in different underwater turbulence intensity, which contains the pressure data that influences refractive index distribution. When the pressure value is conversed to refractive index, the refractive index distribution can be received with the refraction formula. In the condition of same turbulent intensity, the distribution of refractive index presents gradient in the whole region, with disorder and mutations in the local region. With the turbulence intensity increase, the holistic variation of the refractive index in the image is larger, and the refractive index change more tempestuously in the local region. All the above are illustrated by the simulation results with he ray tracing method and turbulent refractive index model. According to different turbulence intensity analysis, it is proved that turbulence causes image distortion and increases noise.

  16. Cluster protocols in Underwater Sensor Networks: a Research Review

    Directory of Open Access Journals (Sweden)

    K. Ovaliadis

    2014-07-01

    Full Text Available Underwater Wireless Sensor Networks (UWSN have different characteristics in relation to terrestrial wireless sensor networks; such as limited bandwidth capacity, high propagation delays and limited battery power. Although there has been much work completed in developing protocols and models for terrestrial networks, these are rarely applicable for underwater sensor networks. Up to today major efforts have been made for designing efficient protocols while considering the underwater communication characteristics. An important issue on this research area is the construction of an efficient clustering algorithm. Clustering in the context of UWSN is important as it contributes a great deal towards the efficient use of energy resources. This paper reviews the most significant cluster based protocols proposed for UWSN. Major performance issues of these protocols with respect to the network conditions such as packet delivery ratio, average packet delay, node mobility effect and energy consumption are examined. The advantages and disadvantages of each protocol are also pointed out.

  17. Robust automatic control system of vessel descent-rise device for plant with distributed parameters “cable – towed underwater vehicle”

    Science.gov (United States)

    Chupina, K. V.; Kataev, E. V.; Khannanov, A. M.; Korshunov, V. N.; Sennikov, I. A.

    2018-05-01

    The paper is devoted to a problem of synthesis of the robust control system for a distributed parameters plant. The vessel descent-rise device has a heave compensation function for stabilization of the towed underwater vehicle on a set depth. A sea state code, parameters of the underwater vehicle and cable vary during underwater operations, the vessel heave is a stochastic process. It means that the plant and external disturbances have uncertainty. That is why it is necessary to use the robust theory for synthesis of an automatic control system, but without use of traditional methods of optimization, because this cable has distributed parameters. The offered technique has allowed one to design an effective control system for stabilization of immersion depth of the towed underwater vehicle for various degrees of sea roughness and to provide its robustness to deviations of parameters of the vehicle and cable’s length.

  18. Apparatus for Changing the Attack Angle of a Cavitator on a Supercavatating Underwater Research Model

    Science.gov (United States)

    2005-07-18

    the Invention 14 The present invention generally relates to an apparatus 15 for changing the attack of a cavitator on a supercavitating 16 underwater...research model. 17 2. Description of the Prior Art 18 Supercavitating underwater vehicles and projectiles are 19 known in the art. One such... supercavitating underwater 20 projectile is described in Harkins et al., U.S. Patent No. 21 5,955,698. This projectile uses a supercavitating nose 22 section that

  19. Autonomous underwater vehicle for research and rescue operations

    CSIR Research Space (South Africa)

    Holtzhausen S

    2008-11-01

    Full Text Available Autonomous under water vehicles are ideal platforms for search and rescue operations. They can also be used for inspection of underwater terrains. These vehicles need to be autonomous and robust to cope with unpredictable current and high pressures...

  20. Game Theory-Based Cooperation for Underwater Acoustic Sensor Networks: Taxonomy, Review, Research Challenges and Directions

    Directory of Open Access Journals (Sweden)

    Dalhatu Muhammed

    2018-02-01

    Full Text Available Exploring and monitoring the underwater world using underwater sensors is drawing a lot of attention these days. In this field cooperation between acoustic sensor nodes has been a critical problem due to the challenging features such as acoustic channel failure (sound signal, long propagation delay of acoustic signal, limited bandwidth and loss of connectivity. There are several proposed methods to improve cooperation between the nodes by incorporating information/game theory in the node’s cooperation. However, there is a need to classify the existing works and demonstrate their performance in addressing the cooperation issue. In this paper, we have conducted a review to investigate various factors affecting cooperation in underwater acoustic sensor networks. We study various cooperation techniques used for underwater acoustic sensor networks from different perspectives, with a concentration on communication reliability, energy consumption, and security and present a taxonomy for underwater cooperation. Moreover, we further review how the game theory can be applied to make the nodes cooperate with each other. We further analyze different cooperative game methods, where their performance on different metrics is compared. Finally, open issues and future research direction in underwater acoustic sensor networks are highlighted.

  1. Game Theory-Based Cooperation for Underwater Acoustic Sensor Networks: Taxonomy, Review, Research Challenges and Directions.

    Science.gov (United States)

    Muhammed, Dalhatu; Anisi, Mohammad Hossein; Zareei, Mahdi; Vargas-Rosales, Cesar; Khan, Anwar

    2018-02-01

    Exploring and monitoring the underwater world using underwater sensors is drawing a lot of attention these days. In this field cooperation between acoustic sensor nodes has been a critical problem due to the challenging features such as acoustic channel failure (sound signal), long propagation delay of acoustic signal, limited bandwidth and loss of connectivity. There are several proposed methods to improve cooperation between the nodes by incorporating information/game theory in the node's cooperation. However, there is a need to classify the existing works and demonstrate their performance in addressing the cooperation issue. In this paper, we have conducted a review to investigate various factors affecting cooperation in underwater acoustic sensor networks. We study various cooperation techniques used for underwater acoustic sensor networks from different perspectives, with a concentration on communication reliability, energy consumption, and security and present a taxonomy for underwater cooperation. Moreover, we further review how the game theory can be applied to make the nodes cooperate with each other. We further analyze different cooperative game methods, where their performance on different metrics is compared. Finally, open issues and future research direction in underwater acoustic sensor networks are highlighted.

  2. Game Theory-Based Cooperation for Underwater Acoustic Sensor Networks: Taxonomy, Review, Research Challenges and Directions

    Science.gov (United States)

    Muhammed, Dalhatu; Anisi, Mohammad Hossein; Vargas-Rosales, Cesar; Khan, Anwar

    2018-01-01

    Exploring and monitoring the underwater world using underwater sensors is drawing a lot of attention these days. In this field cooperation between acoustic sensor nodes has been a critical problem due to the challenging features such as acoustic channel failure (sound signal), long propagation delay of acoustic signal, limited bandwidth and loss of connectivity. There are several proposed methods to improve cooperation between the nodes by incorporating information/game theory in the node’s cooperation. However, there is a need to classify the existing works and demonstrate their performance in addressing the cooperation issue. In this paper, we have conducted a review to investigate various factors affecting cooperation in underwater acoustic sensor networks. We study various cooperation techniques used for underwater acoustic sensor networks from different perspectives, with a concentration on communication reliability, energy consumption, and security and present a taxonomy for underwater cooperation. Moreover, we further review how the game theory can be applied to make the nodes cooperate with each other. We further analyze different cooperative game methods, where their performance on different metrics is compared. Finally, open issues and future research direction in underwater acoustic sensor networks are highlighted. PMID:29389874

  3. The Basic Research for Pulverization of Rice Using Underwater Shock Wave by Electric Discharge

    Directory of Open Access Journals (Sweden)

    M Ide

    2016-09-01

    Full Text Available In recent years, the food self-support rate of Japan is 40%, and this value is the lowest level in major developed countries. This reason includes decreasing of diverting rice consumption in Japan and increasing abandonment of cultivation. Therefore, these problems are solved by using rice powder instead of expensive flour, and we manage to increase the food selfsupport rate. Previously, the rice powder is manufactured by two methods. One is dry type, and the other is wet type. The former is the method getting rice powder by running dried rice to rotating metal, and has a problem which that starch is damaged by heat when processing was performed. The latter is performed same method against wet rice, and has a problem which a large quantity of water is used. As a method to solve these problems, an underwater shock wave is used. Shock wave is the pressure wave which is over speed of sound by discharging high energy in short time. Propagating shock wave in water is underwater shock wave. The characters of underwater shock wave are long duration of shock wave because water density is uniform, water is low price and easy to get and not heat processing. Thinking of industrialization, the electric discharge is used as the generating source of underwater shock wave in the experiment. As the results, the efficiency of obtaining enough grain size, 100ìm, of rice powder was too bad only using the simple processing using underwater shock wave. Therefore, in Okinawa National College of Technology collaborating with us, obtaining rice powder with higher efficiency by using converged underwater shock wave is the goal of this research. In this research, the underwater shock wave with equal energy of the experimental device of underwater shock wave is measured by the optical observation. In addition, the appearance converging underwater shock wave is simulated by numerical analysis, and the pressure appreciation rate between the first wave and converged

  4. Pressure Vessel Steel Research: Belgian Activities

    International Nuclear Information System (INIS)

    Van Walle, E.; Fabry, A.; Ait Abderrahim, H.; Chaouadi, R.; D'hondt, P.; Puzzolante, J.L.; Van de Velde, J.; Van Ransbeeck, T.; Gerard, R.

    1994-03-01

    A review of the Belgian research activities on Nuclear Reactor Pressure Vessel Steels (RPVS) and on related Neutron Dosimetry Aspects is presented. Born out of the surveillance programmes of the Belgian nuclear power plants, this research has lead to the development of material saving techniques, like reconstitution and miniaturization, and to improved neutron dosimetry techniques. A physically- justified RPVS fracture toughness indexation methodology, supported by micro-mechanistic modelling, is based on the elaborate use of the instrumented Charpy impact signal. Computational tools for neutron dosimetry allow to reduce the uncertainties on surveillance capsule fluences significantly

  5. Pressure Vessel Steel Research: Belgian Activities

    Energy Technology Data Exchange (ETDEWEB)

    Van Walle, E; Fabry, A; Ait Abderrahim, H; Chaouadi, R; D` hondt, P; Puzzolante, J L; Van de Velde, J; Van Ransbeeck, T [Centre d` Etude de l` Energie Nucleaire, Mol (Belgium); Gerard, R [TRACTEBEL, Brussels (Belgium)

    1994-03-01

    A review of the Belgian research activities on Nuclear Reactor Pressure Vessel Steels (RPVS) and on related Neutron Dosimetry Aspects is presented. Born out of the surveillance programmes of the Belgian nuclear power plants, this research has lead to the development of material saving techniques, like reconstitution and miniaturization, and to improved neutron dosimetry techniques. A physically- justified RPVS fracture toughness indexation methodology, supported by micro-mechanistic modelling, is based on the elaborate use of the instrumented Charpy impact signal. Computational tools for neutron dosimetry allow to reduce the uncertainties on surveillance capsule fluences significantly.

  6. Annotated Bibliography of Underwater Acoustic Research, 1942-1945.

    Science.gov (United States)

    1983-11-02

    easily be produced in underwater-telephony adapter was quantities by existing facilities at sea-tested on USS LIONFISH . The New the Submarine Base...including 7500 lacquering, waxing, making and yd, with the LIONFISH operating fitting pointers, and maintenance, underway at periscope deptn and the Two...R61 1-452 D24/R62i -462 * USS PERCH (SS-313) USS JORDAN (DE204) D24/R736-564 P42 /R75 9-584 D16/R1388-i 152 D24/R780-603 054 /R992-783 USS LIONFISH (SS

  7. Research on key technology of prognostic and health management for autonomous underwater vehicle

    Science.gov (United States)

    Zhou, Zhi

    2017-12-01

    Autonomous Underwater Vehicles (AUVs) are non-cable and autonomous motional underwater robotics. With a wide range of activities, it can reach thousands of kilometers. Because it has the advantages of wide range, good maneuverability, safety and intellectualization, it becomes an important tool for various underwater tasks. How to improve diagnosis accuracy of the AUVs electrical system faults, and how to repair AUVs by the information are the focus of navy in the world. In turn, ensuring safe and reliable operation of the system has very important significance to improve AUVs sailing performance. To solve these problems, in the paper the prognostic and health management(PHM) technology is researched and used to AUV, and the overall framework and key technology are proposed, such as data acquisition, feature extraction, fault diagnosis, failure prediction and so on.

  8. From Deck Hand to Program Manager - 30 years with Research Vessels

    Science.gov (United States)

    Prince, J. M.

    2012-12-01

    Starting in 1980 as a Mate and Deck Hand and working my way up to Captain, Marine Superintendent, UNOLS Executive Secretary and now as an ONR Research Facilities Program Manager focused on the acquisition of two new Ocean Class Research Vessels, I have witnessed first hand the evolution of the U.S. Academic Research Fleet. The author will focus on a few key events in the evolution of the modern research fleet. As a deck hand, mate and Captain, I was involved in an early multi-disciplinary effort often using two ships working together to conduct sampling and analysis in Physical, Chemical and Biological oceanography. The VERTEX cruises led by John Martin and others used the R/V CAYUSE and R/V WECOMA extensively through out the NE Pacific Ocean conducting research that led to Dr. Martin's Iron Hypothesis. This work and that of others involving trace metal clean sampling and clean laboratories on board our ships pushed many new and demanding requirements for future vessels. As a ship scheduler and as chair of the Research Vessel Operators Committee (RVOC) I saw the increasing use of Remotely Operated Vehicles to complement the work being done with the ALVIN and other occupied submersibles. This led to scheduling challenges and changes to our safety standards, but also to many new opportunities for discoveries on the many mid-ocean ridges and hydro-thermal vent fields. More recently, Autonomous Underwater Vehicles (AUV) and Unmanned Aerial Vehicles (UAV) and aircraft have been used simultaneously with research vessels such as during a multi-PI, multi-ship program in the Monterey Bay. Communications at sea have changed dramatically in the past thirty years. No longer are we limited to reading the data from a spreadsheet over a Single Side Band radio so that the PI ashore can track the progress of a cruise and provide guidance for the next day's sampling. Full bandwidth communications are becoming the norm with the capability of streaming video from an ROV to shore or to

  9. Research Vessel R/V Sikuliaq: Joining the UNOLS Fleet in 2014

    Science.gov (United States)

    Whitledge, T. E.

    2013-12-01

    The global class research vessel R/V Sikuliaq is being constructed on behalf of the NSF to support future scientific studies in high latitude waters. The 261 foot vessel will be capable of breaking 2.5 foot thick ice at 2 knots with an endurance of 45 days at sea and cruising at 11 knots. The R/V Sikuliaq has a beam of 52 feet and a draft of 18.9 feet that will carry 26 scientists and a crew of 20. Berthing accommodations are a combination of single/double rooms with one stateroom and the common areas of the vessel are designed for ADA access and accommodations. The total laboratory space (main, analytical, electronics, wet, upper, and Baltic room are 2100 square feet. The 4360 square foot working deck that is approximately 70 feet in length will accommodate 2-4 vans and multiple science operations. The vessel design strives to have the lowest possible environmental impact, including a low underwater-radiated noise signature. The science systems are prescribed to be state-of-the-art for bottom mapping, over-the-side 'hands free' gear handling, broad band communications and scientific walk-in freezer and environmental chamber. More details and photos of the construction progress are available on the website at www.sfos.uaf.edu/arrv. The vessel was launched in October 2012 and delivery to the University of Alaska Fairbanks is scheduled for November 2013. Scientific operations following testing and science sea trials are planned to start in summer of 2014. Questions about the science systems or vessel capabilities should be directed to Terry Whitledge (terry@ims.uaf.edu).

  10. Research program plan: reactor vessels. Volume 1

    International Nuclear Information System (INIS)

    Vagins, M.; Taboada, A.

    1985-07-01

    The ability of the licensing staff of the NRC to make decisions concerning the present and continuing safety of nuclear reactor pressure vessels under both normal and abnormal operating conditions is dependent upon the existence of verified analysis methods and a solid background of applicable experimental data. It is the role of this program to provide both the analytical methods and the experimental data needed. Specifically, this program develops fracture mechanics analysis methods and design criteria for predicting the stress levels and flaw sizes required for crack initiation, propagation, and arrest in LWR pressure vessels under all known and postulated operations conditions. To do this, not only must the methods be developed but they must be experimentally validated. Further, the materials data necessary for input to these analytical methods must be developed. Thus, in addition to methods development and large scale experimental verification this program also develops data to show that slow-load fracture toughness, rapid-load fracture toughness, and crack arrest toughness obtained from small laboratory specimens are truly representative of the toughness characteristics of the material behavior in pressure vessels in both the unirradiated and the irradiated conditions

  11. Survey and Recording Technologies in Italian Underwater Cultural Heritage: Research and Public Access Within the Framework of the 2001 UNESCO Convention

    Science.gov (United States)

    Secci, Massimiliano

    2017-08-01

    The 2001 UNESCO Convention on the Protection of the Underwater Cultural Heritage is slowly but peremptorily becoming a standard reference tool for underwater archaeology and underwater cultural heritage management. The many provisions included within the Convention touch on many aspects that are key to an effective protection and promotion of the underwater cultural heritage. Within the web of these provisions many aspects are gaining consideration and driving research in underwater archaeology worldwide. These provisions, when seen within a wider frame of social, economical and technological dynamics, pinpoint many aspects requiring further scrutiny from the disciplinary circle. In the framework of the 2001 UNESCO Convention, this article will analyze the path traveled in technological acquisition in the practice of Italian underwater archaeology and how this has affected the approach to underwater cultural heritage management, particularly highlighting how this process has been further influenced by the adoption in 2001 of the Convention and Italy's ratification of it in 2010.

  12. Research Vessel R/V Sikuliaq: A New Asset For The UNOLS Fleet

    Science.gov (United States)

    Whitledge, T. E.

    2012-12-01

    The research vessel R/V Sikuliaq is currently being constructed on behalf of the NSF to support future scientific studies in high latitude waters. The 261 foot global class vessel will be capable of breaking 2.5 foot thick ice at 2 knots with an endurance of 45 days at sea and cruising at 11 knots. The R/V Sikuliaq will have a beam of 52 feet and a draft of 18.9 feet that will carry 26 scientists and a crew of 20. Berthing accommodations are a combination of single/double rooms with one stateroom and the common areas of the vessel are designed for ADA access and accommodations. The total laboratory space (main, analytical, electronics, wet, upper, and Baltic room will be 2100 square feet. The 4360 square foot working deck that is approximately 70 feet in length will accommodate 2-4 vans and multiple science operations. The vessel design strives to have the lowest possible environmental impact, including a low underwater-radiated noise signature. The science systems are prescribed to be state-of-the-art for bottom mapping, over-the-side "hands free" gear handling, broad band communications and scientific walk-in freezer and environmental chamber. More details and photos of the construction progress are available on the website at www.sfos.uaf.edu/arrv. The shipyard schedule has a launch date of October 2012 and delivery to the University of Alaska Fairbanks in July 2013. Scientific operations following trials and testing is planned to start in January 2014. Questions about the science systems or vessel capabilities should be directed to Terry Whitledge (terry@ims.uaf.edu).;

  13. Reactor pressure vessel structural integrity research

    International Nuclear Information System (INIS)

    Pennell, W.E.; Corwin, W.R.

    1994-01-01

    Development continues on the technology used to assess the safety of irradiation-embrittled nuclear reactor pressure vessels (RPVs) containing flaws. Fracture mechanics tests on RPV steel, coupled with detailed elastic-plastic finite-element analyses of the crack-tip stress fields, have shown that (1) constraint relaxation at the crack tip of shallow surface flaws results in increased data scatter but no increase in the lower-bound fracture toughness, (2) the nil ductility temperature (NDT) performs better than the reference temperature for nil ductility transition (RT NDT ) as a normalizing parameter for shallow-flaw fracture toughness data, (3) biaxial loading can reduce the shallow-flaw fracture toughness, (4) stress-based dual-parameter fracture toughness correlations cannot predict the effect of biaxial loading on shallow-flaw fracture toughness because in-plane stresses at the crack tip are not influenced by biaxial loading, and (5) an implicit strain-based dual-parameter fracture toughness correlation can predict the effect of biaxial loading on shallow-flaw fracture toughness. Experimental irradiation investigations have shown that (1) the irradiation-induced shift in Charpy V-notch vs temperature behavior may not be adequate to conservatively assess fracture toughness shifts due to embrittlement, and (2) the wide global variations of initial chemistry and fracture properties of a nominally uniform material within a pressure vessel may confound accurate integrity assessments that require baseline properties

  14. Development of an integrated data acquision system for research vessels

    Digital Repository Service at National Institute of Oceanography (India)

    Mehra, P.; Desai, R.G.P.

    This article describes an integrated data acquisition system (IDAS) designed and developed for multi-oceanographic research vessels. The prime motivation was to provide a flexible system, which could be used in the context of ocean related...

  15. Construction Progress and Science Planning for the New Research Vessel R/V Sikuliaq

    Science.gov (United States)

    Whitledge, T. E.

    2011-12-01

    The research vessel R/V Sikuliaq (pronounced [see-KOO-lee-auk]) is currently being constructed on behalf of the NSF to support future scientific studies in high latitude waters. The 261 foot global class vessel will be capable of breaking 2.5 foot thick ice at 2 knots with an endurance of 45 days at sea and cruising at 11 knots. The R/V Sikuliaq will have a beam of 52 feet and a draft of 18.9 feet that will carry 26 scientists and a crew of 20. Berthing accommodations are a combination of single/double rooms with one stateroom and the common areas of the vessel are designed for ADA access and accommodations. The total laboratory space (main, analytical, electronics, wet, upper, and Baltic room will be 2100 square feet. The 4360 square foot working deck that is approximately 70 feet in length will accommodate 2-4 vans and multiple science operations. The vessel design strives to have the lowest possible environmental impact, including a low underwater-radiated noise signature. The science systems are prescribed to be state-of-the-art for bottom mapping, over-the-side "hands free" gear handling, broad band communications and scientific walk-in freezer and environmental chamber. More details and photos of the construction progress are available on the website at www.sfos.uaf.edu/arrv. The tentative shipyard schedule has a launch date of June 2012 and delivery to the University of Alaska Fairbanks in June 2013. Scientific operations following trials and testing is planned to start in January 2014. A Sikuliaq science planning workshop has been arranged for 18-19 February 2012 in Salt Lake City, UT just prior to the 2012 Ocean Sciences meeting. Interested participants should contact Terry Whitledge (terry@ims.uaf.edu).

  16. Possible research program on a large scale nuclear pressure vessel

    International Nuclear Information System (INIS)

    1983-01-01

    The nuclear pressure vessel structural integrity is actually one of the main items in the nuclear plants safety field. An international study group aimed at investigating the feasibility of a ''possible research program'' on a scale 1:1 LWR pressure vessel. This report presents the study group's work. The different research programs carried out or being carried out in various countries of the European Community are presented (phase I of the study). The main characteristics of the vessel considered for the program and an evaluation of activities required for making them available are listed. Research topic priorities from the different interested countries are summarized in tables (phase 2); a critical review by the study group of the topic is presented. Then, proposals for possible experimental programs and combination of these programs are presented, only as examples of possible useful research activities. The documents pertaining to the results of phase I inquiry performed by the study group are reported in the appendix

  17. Routing Protocols for Underwater Wireless Sensor Networks: Taxonomy, Research Challenges, Routing Strategies and Future Directions.

    Science.gov (United States)

    Khan, Anwar; Ali, Ihsan; Ghani, Abdullah; Khan, Nawsher; Alsaqer, Mohammed; Rahman, Atiq Ur; Mahmood, Hasan

    2018-05-18

    Recent research in underwater wireless sensor networks (UWSNs) has gained the attention of researchers in academia and industry for a number of applications. They include disaster and earthquake prediction, water quality and environment monitoring, leakage and mine detection, military surveillance and underwater navigation. However, the aquatic medium is associated with a number of limitations and challenges: long multipath delay, high interference and noise, harsh environment, low bandwidth and limited battery life of the sensor nodes. These challenges demand research techniques and strategies to be overcome in an efficient and effective fashion. The design of routing protocols for UWSNs is one of the promising solutions to cope with these challenges. This paper presents a survey of the routing protocols for UWSNs. For the ease of description, the addressed routing protocols are classified into two groups: localization-based and localization-free protocols. These groups are further subdivided according to the problems they address or the major parameters they consider during routing. Unlike the existing surveys, this survey considers only the latest and state-of-the-art routing protocols. In addition, every protocol is described in terms of its routing strategy and the problem it addresses and solves. The merit(s) of each protocol is (are) highlighted along with the cost. A description of the protocols in this fashion has a number of advantages for researchers, as compared to the existing surveys. Firstly, the description of the routing strategy of each protocol makes its routing operation easily understandable. Secondly, the demerit(s) of a protocol provides (provide) insight into overcoming its flaw(s) in future investigation. This, in turn, leads to the foundation of new protocols that are more intelligent, robust and efficient with respect to the desired parameters. Thirdly, a protocol can be selected for the appropriate application based on its described

  18. A PROPOSAL FOR A SUSTAINABLE MODEL BASED UPON UNDERWATER TOURISM RESEARCH IN AYVALIK

    Directory of Open Access Journals (Sweden)

    A. GÖKDENİZ

    2013-03-01

    Full Text Available Underwater sports are the activities being done with the aims of witnessing the beauties, hunting, taking photos, the ecology and the archaeology of underwater analysing or finding out the human being’s boundaries by improving the physical and psychological skills of men. The initial aim of this project is to increase the underwater flora and the fauna heritage of Ayvalık and to bring them in tourism. Ayvalık is on the west coast of Turkey. It is getting more and more famous with its underwater richness. Also, to form a new underwater sports centre in order to contribute to the improvement of the region. By providing visual attractiveness, the tourists related to underwater sports will pay attention to Ayvalık and underwater tourism will contribute much to the economy of the region. The aim of this project is to improve the underwater sports which is now a hobby than a sport. In Ayvalık Underwater World study, we dealt with 247 divers and 4 underwater sports club. In this study, we analysed the expectation, satisfaction, demographic and economic level of 247 divers about the services in the region. Interview technique has been used in the study on the 4 underwater sports clubs which are hosting divers. As a conclusion, a report has been prepared in which detailed information and proposals are presented by developing a sustainable marketing model concerned with the underwater sports for those who want to possess information, shareholders of the sector and make analyse about tourism.

  19. Underwater welding of steel

    International Nuclear Information System (INIS)

    Ibarra, S.; Olson, D.L.

    1992-01-01

    A fundamental basis to understand the behavior of wet underwater welding of steel is introduced. Both the pyrometallurgical and physical metallurgy concepts are discussed. Modifications of welding consumables and practice are suggested. This chapter promotes further contributions of meatllurgical research to improve and promote wet underwater welding. (orig.)

  20. Resources for Underwater Robotics Education

    Science.gov (United States)

    Wallace, Michael L.; Freitas, William M.

    2016-01-01

    4-H clubs can build and program underwater robots from raw materials. An annotated resource list for engaging youth in building underwater remotely operated vehicles (ROVs) is provided. This article is a companion piece to the Research in Brief article "Building Teen Futures with Underwater Robotics" in this issue of the "Journal of…

  1. Developing national on-line services to annotate and analyse underwater imagery in a research cloud

    Science.gov (United States)

    Proctor, R.; Langlois, T.; Friedman, A.; Davey, B.

    2017-12-01

    Fish image annotation data is currently collected by various research, management and academic institutions globally (+100,000's hours of deployments) with varying degrees of standardisation and limited formal collaboration or data synthesis. We present a case study of how national on-line services, developed within a domain-oriented research cloud, have been used to annotate habitat images and synthesise fish annotation data sets collected using Autonomous Underwater Vehicles (AUVs) and baited remote underwater stereo-video (stereo-BRUV). Two developing software tools have been brought together in the marine science cloud to provide marine biologists with a powerful service for image annotation. SQUIDLE+ is an online platform designed for exploration, management and annotation of georeferenced images & video data. It provides a flexible annotation framework allowing users to work with their preferred annotation schemes. We have used SQUIDLE+ to sample the habitat composition and complexity of images of the benthos collected using stereo-BRUV. GlobalArchive is designed to be a centralised repository of aquatic ecological survey data with design principles including ease of use, secure user access, flexible data import, and the collection of any sampling and image analysis information. To easily share and synthesise data we have implemented data sharing protocols, including Open Data and synthesis Collaborations, and a spatial map to explore global datasets and filter to create a synthesis. These tools in the science cloud, together with a virtual desktop analysis suite offering python and R environments offer an unprecedented capability to deliver marine biodiversity information of value to marine managers and scientists alike.

  2. Arctic research vessel design would expand science prospects

    Science.gov (United States)

    Elsner, Robert; Kristensen, Dirk

    The U.S. polar marine science community has long declared the need for an arctic research vessel dedicated to advancing the study of northern ice-dominated seas. Planning for such a vessel began 2 decades ago, but competition for funding has prevented construction. A new design program is underway, and it shows promise of opening up exciting possibilities for new research initiatives in arctic marine science.With its latest design, the Arctic Research Vessel (ARV) has grown to a size and capability that will make it the first U.S. academic research vessel able to provide access to the Arctic Ocean. This ship would open a vast arena for new studies in the least known of the world's seas. These studies promise to rank high in national priority because of the importance of the Arctic Ocean as a source of data relating to global climate change. Other issues that demand attention in the Arctic include its contributions to the world's heat budget, the climate history buried in its sediments, pollution monitoring, and the influence of arctic conditions on marine renewable resources.

  3. ROV-based Underwater Vision System for Intelligent Fish Ethology Research

    Directory of Open Access Journals (Sweden)

    Rui Nian

    2013-09-01

    Full Text Available Fish ethology is a prospective discipline for ocean surveys. In this paper, one ROV-based system is established to perform underwater visual tasks with customized optical sensors installed. One image quality enhancement method is first presented in the context of creating underwater imaging models combined with homomorphic filtering and wavelet decomposition. The underwater vision system can further detect and track swimming fish from the resulting images with the strategies developed using curve evolution and particular filtering, in order to obtain a deeper understanding of fish behaviours. The simulation results have shown the excellent performance of the developed scheme, in regard to both robustness and effectiveness.

  4. Underwater nuclear power plant structure

    International Nuclear Information System (INIS)

    Severs, S.; Toll, H.V.

    1982-01-01

    A structure for an underwater nuclear power generating plant comprising a triangular platform formed of tubular leg and truss members upon which are attached one or more large spherical pressure vessels and one or more small cylindrical auxiliary pressure vessels. (author)

  5. The industrial research project: “Blu-Archeosys – Innovative Technologies and Advanced Systems as Support in Underwater Archaeology”

    Directory of Open Access Journals (Sweden)

    Salvatore Lorusso

    2003-02-01

    Full Text Available The reasons of the research about new technologies as support in naval and underwater archaeology or, more generally, in waters archaeology are various and described in this work, where the characteristics of the research project “BLU-ARCHEOSYS – Innovative Technologies and Advanced SYStems as Support in Underwater ARCHaeology” are illustrated. This industrial research project faces problems regarding innovative technologies and instruments in waters archaeology and it comprehends synergic steps and joined works among skilled professionals that have the competences to interpret qualitative and/or quantitative data within an artistic – historical and technical – historical study, also with the involvement of various public and private institutions. The BLUARCHEOSYS project has, in fact, the objective to create technologies that have a reply in underwater archaeology and contemporaneously in other sectors. In particular, starting from the methodological way that spans from the discovery in underwater or subaerial environment to the collocation of the objects in museums, the intent is to support the different methodological stages with specific tools and innovative technologies. The education project, presented to the Ministry with the research one, is articulated in the different branches of artistic-historical character, of the management, normative and operative character, and of the technical-diagnostic-material-preservative character. The professionals will have not only theoretical knowledge about standard and consolidated technologies, but they will be also experts about methodologies, in particular the diagnostic ones, that put in field the innovative tools evaluated in the project, with consequent competitive advantage in the working field, more and more demanding specific sector competences.

  6. Vessel-related problems in severe accidents, International Research Projects

    International Nuclear Information System (INIS)

    Figueras, J. M.

    2000-01-01

    The paper describes those most relevant aspects of research programmes and projects, on the behavior of vessel during severe accidents with partial or total reactor core fusion, performed during the last twenty years or still on-going projects, by countries or international organizations in the nuclear community, presenting the most important technical aspects, in particular the results achieved, as well as the financial and organisational aspects. The paper concludes that, throughout a joint effort of the international nuclear community, in which Spain has been present via private and public organizations, actually exist a reasonable technical and experimental knowledge of the vessel in case of severe accidents, but still there are aspects not fully solved which are the basis for continuing some programmes and for proposal of new ones. (Author)

  7. Research on the underwater target imaging based on the streak tube laser lidar

    Science.gov (United States)

    Cui, Zihao; Tian, Zhaoshuo; Zhang, Yanchao; Bi, Zongjie; Yang, Gang; Gu, Erdan

    2018-03-01

    A high frame rate streak tube imaging lidar (STIL) for real-time 3D imaging of underwater targets is presented in this paper. The system uses 532nm pulse laser as the light source, the maximum repetition rate is 120Hz, and the pulse width is 8ns. LabVIEW platform is used in the system, the system control, synchronous image acquisition, 3D data processing and display are realized through PC. 3D imaging experiment of underwater target is carried out in a flume with attenuation coefficient of 0.2, and the images of different depth and different material targets are obtained, the imaging frame rate is 100Hz, and the maximum detection depth is 31m. For an underwater target with a distance of 22m, the high resolution 3D image real-time acquisition is realized with range resolution of 1cm and space resolution of 0.3cm, the spatial relationship of the targets can be clearly identified by the image. The experimental results show that STIL has a good application prospect in underwater terrain detection, underwater search and rescue, and other fields.

  8. Underwater robots

    CERN Document Server

    Antonelli, Gianluca

    2014-01-01

    This book, now at the third edition, addresses the main control aspects in underwater manipulation tasks. The mathematical model with significant impact on the control strategy is discussed. The problem of controlling a 6-degrees-of-freedoms autonomous underwater vehicle is deeply investigated and a survey of fault detection/tolerant strategies for unmanned underwater vehicles is provided. Inverse kinematics, dynamic and interaction control for underwater vehicle-manipulator systems are then discussed. The code used to generate most of the numerical simulations is made available and briefly discussed.       

  9. Research and development of the prestressed concrete reactor vessel

    International Nuclear Information System (INIS)

    Shiozawa, Shoji; Omata, Ippei; Nakamura, Norio

    1975-01-01

    Compared with the steel reactor vessel, the prestressed concrete reactor vessel (PCRV) is said to be superior in safety and economy. One of the characteristics of the high temperature gas cooled reactor (HTGR) is the adoption of the PCRV instead of the steel reactor vessel to ensure safety. In order to improve safety characteristics, it is necessary for the PCRV to be provided with more reliable functions. When the multi-purpose HTGR or the gas cooled fast breeder reactor (GCFR) are realized in future, more severe conditions of technology will be imposed on the PCRV, and accordingly, technical developments are now increasingly required. IHI is now proceeding with the technical research and development on the PCRV, in which a basic study of its liner cooling system has already been completed. In this study applying a large cylindrical PCRV model, comparison was made between experimental data and analyses concerning the liner cooling system, and the results of analytical technique have been evaluated. The analytical technique established this time is applicable to the estimation of temperature distribution in the concrete of a large PCRV and also to the evaluation of the liner cooling system. (auth.)

  10. Underwater Gliders: A Review

    OpenAIRE

    Javaid Muhammad Yasar; Ovinis Mark; Nagarajan T; Hashim Fakhruldin B M

    2014-01-01

    Underwater gliders are a type of underwater vehicle that transverse the oceans by shifting its buoyancy, during which its wings develop a component of the downward motion in the horizontal plane, thus producing a forward force. They are primarily used in oceanography sensing and data collection and play an important role in ocean research and development. Although there have been considerable developments in these gliders since the development of the first glider concept in 1989, to date, no ...

  11. Summary engineering description of underwater fuel storage facility for foreign research reactor spent nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Dahlke, H.J.; Johnson, D.A.; Rawlins, J.K.; Searle, D.K.; Wachs, G.W.

    1994-10-01

    This document is a summary description for an Underwater Fuel Storage Facility (UFSF) for foreign research reactor (FRR) spent nuclear fuel (SNF). A FRR SNF environmental Impact Statement (EIS) is being prepared and will include both wet and dry storage facilities as storage alternatives. For the UFSF presented in this document, a specific site is not chosen. This facility can be sited at any one of the five locations under consideration in the EIS. These locations are the Idaho National Engineering Laboratory, Savannah River Site, Hanford, Oak Ridge National Laboratory, and Nevada Test Site. Generic facility environmental impacts and emissions are provided in this report. A baseline fuel element is defined in Section 2.2, and the results of a fission product analysis are presented. Requirements for a storage facility have been researched and are summarized in Section 3. Section 4 describes three facility options: (1) the Centralized-UFSF, which would store the entire fuel element quantity in a single facility at a single location, (2) the Regionalized Large-UFSF, which would store 75% of the fuel element quantity in some region of the country, and (3) the Regionalized Small-UFSF, which would store 25% of the fuel element quantity, with the possibility of a number of these facilities in various regions throughout the country. The operational philosophy is presented in Section 5, and Section 6 contains a description of the equipment. Section 7 defines the utilities required for the facility. Cost estimates are discussed in Section 8, and detailed cost estimates are included. Impacts to worker safety, public safety, and the environment are discussed in Section 9. Accidental releases are presented in Section 10. Standard Environmental Impact Forms are included in Section 11.

  12. Underwater 3D filming

    Directory of Open Access Journals (Sweden)

    Roberto Rinaldi

    2014-12-01

    Full Text Available After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie’s box offices due to the overall quality of its products. Special environments such as space (“Gravity” and the underwater realm look perfect to be reproduced in 3D. “Filming in space” was possible in “Gravity” using special effects and computer graphic. The underwater realm is still difficult to be handled. Underwater filming in 3D was not that easy and effective as filming in 2D, since not long ago. After almost 3 years of research, a French, Austrian and Italian team realized a perfect tool to film underwater, in 3D, without any constrains. This allows filmmakers to bring the audience deep inside an environment where they most probably will never have the chance to be.

  13. Underwater Gliders by Dr. Kevin Smith [video

    OpenAIRE

    Naval Postgraduate School Physics

    2015-01-01

    NPS Physics NPS Physics Research Projects Underwater glider research is currently underway in the physics department at the naval postgraduate in Monterey Ca. Dr. Kevin Smith is a specialist in underwater acoustics and sonar systems. He and his team are currently focused on autonomous underwater gliders and developing systems capable of detecting parameters in the ocean and listening for various sources of sound.

  14. The Research on Improved Companding Transformation for Reducing PAPR in Underwater Acoustic OFDM Communication System

    Directory of Open Access Journals (Sweden)

    Jinqiu Wu

    2016-01-01

    Full Text Available To solve the problem of the high peak-to-average power ratio (PAPR in Orthogonal Frequency Division Multiplexing (OFDM for the underwater acoustic communication system, the paper offers a method of reducing PAPR which combines the amplitude limiting and the improved nonlinear transformation. Traditional amplitude limiting technique can reduce PAPR in OFDM system effectively, at the cost of reducing the bit error rate (BER. However the companding transformation has far less computation complexity than SLM or PTS technologies and can improve the BER performance compared to the amplitude limiting technique simultaneously. The paper combines these two kinds of techniques, takes full use of advantages of the two method, and puts forward a low-complexity scheme choosing parameters that are more appropriate to the underwater acoustic field, with the result of improved BER performance even in lower SNR. Both simulation and experiment results show that the new method which combines clipping and companding transformation can effectively reduce the PAPR in the underwater acoustic OFDM communication system and improve the BER performance simultaneously.

  15. Energy Consumption Research of Mobile Data Collection Protocol for Underwater Nodes Using an USV

    Directory of Open Access Journals (Sweden)

    Zhichao Lv

    2018-04-01

    Full Text Available The Unmanned Surface Vehicle (USV integrated with an acoustic modem is a novel mobile vehicle for data collection, which has an advantage in terms of mobility, efficiency, and collection cost. In the scenario of data collection, the USV is controlled autonomously along the planning trajectory and the data of underwater nodes are dynamically collected. In order to improve the efficiency of data collection and extend the life of the underwater nodes, a mobile data collection protocol for underwater nodes using the USV was proposed. In the protocol, the stop-and-wait ARQ transmission mechanism is adopted, where the duty cycle is designed considering the ratio between the sleep mode and the detection mode, and the transmission ratio is defined by the duty cycle, wake-up signal cycles, and USV’s speed. According to protocol, the evaluation index for energy consumption is constructed based on the duty cycle and the transmission ratio. The energy consumption of the protocol is simulated and analyzed using the mobile communication experiment data of USV, taking into consideration USV’s speed, data sequence length, and duty cycle. Optimized protocol parameters are identified, which in turn denotes the proposed protocol’s feasibility and effectiveness.

  16. Underwater Ranging

    OpenAIRE

    S. P. Gaba

    1984-01-01

    The paper deals with underwater laser ranging system, its principle of operation and maximum depth capability. The sources of external noise and methods to improve signal-to-noise ratio are also discussed.

  17. DEPSCOR: Research on ARL's Intelligent Control Architecture: Hierarchical Hybrid-Model Based Design, Verification, Simulation, and Synthesis of Mission Control for Autonomous Underwater Vehicles

    National Research Council Canada - National Science Library

    Kumar, Ratnesh; Holloway, Lawrence E

    2007-01-01

    ... modeling, verification, simulation and automated synthesis of coordinators has lead to research in this area. We have worked and are working on these issues with Applied Research Laboratory (ARL) at Pennsylvania State University (PSU) who have designed autonomous underwater vehicles for over 50 years primarily under the support of the U.S. Navy through the Office of Naval Research (ONR).

  18. Study on operation conditions and an operation system of a nuclear powered submersible research vessel, 'report of working group on application of a very small nuclear reactor to an ocean research'

    International Nuclear Information System (INIS)

    Ura, Tamaki; Takamasa, Tomoji; Nishimura, Hajime

    2001-07-01

    JAERI has studied on design of a nuclear powered submersible research vessel, which will navigate under sea mainly in the Arctic Ocean, as a part of the design activity of advanced marine reactors. This report describes operation conditions and an operating system of the vessel, which were discussed by the specialists of hull design, sound positioning, ship motions and oceanography, etc. The design conditions on ship motions for submersible vessels were surveyed considering regulations in our country, and ship motions were evaluated in the cases of underwater and surface navigations taking account of observation activities in the Arctic Ocean. The effect of ship motions on the compact nuclear reactor SCR was assessed. A submarine transponder system and an on-ice communication buoy system were examined as a positioning and communication system, supposing the activity under ice. The interval between transponders or communication buoys was recommended as 130 km. Procedures to secure safety of nuclear powered submersible research vessel were discussed according to accidents on the hull or the nuclear reactor. These results were reflected to the concept of the nuclear powered submersible research vessel, and subjects to be settled in the next step were clarified. (author)

  19. Study on operation conditions and an operation system of a nuclear powered submersible research vessel, 'report of working group on application of a very small nuclear reactor to an ocean research'

    Energy Technology Data Exchange (ETDEWEB)

    Ura, Tamaki [Tokyo Univ., Tokyo (Japan); Takamasa, Tomoji [Tokyo Univ. of Mercantile Marine, Tokyo (Japan); Nishimura, Hajime [Japan Marine Science and Technology Center, Yokosuka, Kanagawa (JP)] [and others

    2001-07-01

    JAERI has studied on design of a nuclear powered submersible research vessel, which will navigate under sea mainly in the Arctic Ocean, as a part of the design activity of advanced marine reactors. This report describes operation conditions and an operating system of the vessel, which were discussed by the specialists of hull design, sound positioning, ship motions and oceanography, etc. The design conditions on ship motions for submersible vessels were surveyed considering regulations in our country, and ship motions were evaluated in the cases of underwater and surface navigations taking account of observation activities in the Arctic Ocean. The effect of ship motions on the compact nuclear reactor SCR was assessed. A submarine transponder system and an on-ice communication buoy system were examined as a positioning and communication system, supposing the activity under ice. The interval between transponders or communication buoys was recommended as 130 km. Procedures to secure safety of nuclear powered submersible research vessel were discussed according to accidents on the hull or the nuclear reactor. These results were reflected to the concept of the nuclear powered submersible research vessel, and subjects to be settled in the next step were clarified. (author)

  20. Safety aspects for underwater vehicles

    Digital Repository Service at National Institute of Oceanography (India)

    Madhan, R.; Navelkar, G.S.; Desa, E.S.; Afzulpurkar, S.; Prabhudesai, S.P.; Dabholkar, N.; Mascarenhas, A.A.M.Q.; Maurya, P.

    instrumentation is intelligent small Autonomous Underwater Vehicles (AUV’s), autonomous profilers, gliders [1], etc. The ultimate aim in all autonomous platforms research and development is to reach the stage of unescorted missions with minimum failures...

  1. Design of Autonomous Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Tadahiro Hyakudome

    2011-03-01

    Full Text Available There are concerns about the impact that global warming will have on our environment, and which will inevitably result in expanding deserts and rising water levels. While a lot of underwater vehicles are utilized, AUVs (Autonomous Underwater Vehicle were considered and chosen, as the most suitable tool for conduction survey concerning these global environmental problems. AUVs can comprehensive survey because the vehicle does not have to be connected to the support vessel by tether cable. When such underwater vehicles are made, it is necessary to consider about the following things. 1 Seawater and Water Pressure Environment, 2 Sink, 3 There are no Gas or Battery Charge Stations, 4 Global Positioning System cannot use, 5 Radio waves cannot use. In the paper, outline of above and how deal about it are explained.

  2. Experimental Research on the Dynamic Response of Floating Structures with Coatings Subjected to Underwater Explosion

    Directory of Open Access Journals (Sweden)

    Feng Xiao

    2014-01-01

    Full Text Available This paper presents an experimental investigation into the dynamic response of three free floating stiffened metal boxes with protective coatings subjected to underwater explosion (UNDEX. One box was kept intact while the other two were, respectively, covered with monolithic coatings and chiral honeycomb coatings. Three groups of live fire tests with different attack angles and stand-off distances were conducted. The acceleration on the stiffener and strain peak on the bottom hull were selected as the major comparative criterions. Test results show that the impulse transmitted to the structure at the initial stage can be reduced, owing to the coating flexibility and fluid-structure interaction mechanism. Consequently, the acceleration peaks induced by both shock wave and bubble pulse were reduced. The shock environment can be more effectively improved by honeycomb coating when compared with monolithic coating. Most of the strain peaks decreased to a certain extent, but some of them were notably manifested, especially for honeycomb coating. The test affirms the fact that soft coating can cause stress concentration on the shell that is in direct contact with the coating due to the impedance mismatch between the interfaces of materials. A softer rubber coating induces a greater magnitude of strain.

  3. RESEARCH OF REFRIGERATION SYSTEMS FAILURES IN POLISH FISHING VESSELS

    Directory of Open Access Journals (Sweden)

    Waldemar KOSTRZEWA

    2013-07-01

    Full Text Available Temperature is a basic climatic parameter deciding about the quality change of fishing products. Time, after which qualitative changes of caught fish don’t exceed established, acceptable range, is above all the temperature function. Temperature reduction by refrigeration system of the cargo hold is a basic technical method, which allows extend transport time. Failures of refrigeration systems in fishing vessels have a negative impact on the environment in relation to harmful refrigerants emission. The paper presents the statistical analysis of failures occurred in the refrigeration systems of Polish fishing vessels in 2007‐2011 years. Analysis results described in the paper can be a base to draw up guidelines, both for designers as well as operators of the marine refrigeration systems.

  4. 77 FR 60042 - Safety Zone; Research Vessel SIKULIAQ Launch, Marinette, WI

    Science.gov (United States)

    2012-10-02

    ...: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone on the Menominee River in Marinette Wisconsin. This zone is intended to restrict vessels from a portion of Menominee River during the launching of the Research vessel SIKULIAQ, on October 13th, 2012. This temporary safety...

  5. The underwater acoustic environment at SGaan Kinghlas-Bowie Seamount Marine Protected Area: Characterizing vessel traffic and associated noise using satellite AIS and acoustic datasets.

    Science.gov (United States)

    Allen, Ainsley S; Yurk, Harald; Vagle, Svein; Pilkington, James; Canessa, Rosaline

    2018-03-01

    Vessel traffic is one of the most wide-spread anthropogenic contributors to ocean noise worldwide and has the potential to alter ecosystems upon which cetaceans and other acoustically sensitive marine organisms rely. Canada's SGaan Kinghlas-Bowie Seamount Marine Protected Area (SK-B MPA) is one such area whose productive ecosystem could benefit from greater monitoring of human induced threats in order to inform management. Despite earning official designation as a Marine Protected Area under the Oceans Act in 2008, little remains known about vessel traffic in the region and the associated potential impacts on vulnerable marine species. Therefore, to increase our understanding of vessel traffic and accompanying noise at SK-B MPA, satellite AIS and acoustic data were investigated. The results of this study suggest that variations in ambient sound levels in the region are driven by near and distant shipping events, thus having implications for future management of the MPA. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Underwater running device

    International Nuclear Information System (INIS)

    Kogure, Sumio; Matsuo, Takashiro; Yoshida, Yoji

    1996-01-01

    An underwater running device for an underwater inspection device for detecting inner surfaces of a reactor or a water vessel has an outer frame and an inner frame, and both of them are connected slidably by an air cylinder and connected rotatably by a shaft. The outer frame has four outer frame legs, and each of the outer frame legs is equipped with a sucker at the top end. The inner frame has four inner frame legs each equipped with a sucker at the top end. The outer frame legs and the inner frame legs are each connected with the outer frame and the inner frame by the air cylinder. The outer and the inner frame legs can be elevated or lowered (or extended or contracted) by the air cylinder. The sucker is connected with a jet pump-type negative pressure generator. The device can run and move by repeating attraction and releasing of the outer frame legs and the inner frame legs alternately while maintaining the posture of the inspection device stably. (I.N.)

  7. Underwater target positioning with a single acoustic sensor

    Digital Repository Service at National Institute of Oceanography (India)

    David, M-S; Pascoal, A.M.; Joaquin, A.

    The availability of reliable underwater positioning systems to localize one or more vehicles simultaneously based on information received on-board a support ship or an autonomous surface vessel is key to the operation of some classes of AUVs...

  8. Research to sustain cases for Magnox-reactor steel pressure vessels

    International Nuclear Information System (INIS)

    Graham, W.J.

    1997-01-01

    Britain's Magnox Electric plc owns and operates six power stations, each of which has twin gas-cooled reactors of the Magnox-fuel type. The older group of four power stations has steel pressure-circuits. The reactor cores are housed within spherical, steel vessels. This article describes some of the research which is undertaken to sustain the safety cases for these steel vessels which have now been in operation for just over 30 years. (author) 2 figs., 4 refs

  9. Underwater Gliders: A Review

    Directory of Open Access Journals (Sweden)

    Javaid Muhammad Yasar

    2014-07-01

    Full Text Available Underwater gliders are a type of underwater vehicle that transverse the oceans by shifting its buoyancy, during which its wings develop a component of the downward motion in the horizontal plane, thus producing a forward force. They are primarily used in oceanography sensing and data collection and play an important role in ocean research and development. Although there have been considerable developments in these gliders since the development of the first glider concept in 1989, to date, no review of these gliders have been done. This paper reviews existing underwater gliders, with emphasis on their respective working principles, range and payload capacity. All information on gliders available in the public domain or published in literature from the year 2000-2013 was reviewed. The majority of these gliders have an operational depth of 1000 m and a payload of less than 25 kg. The exception is a blend-body shape glider, which has a payload of approximately 800 kg and an operational depth around about 300 m. However, the commercialization of these gliders has been limited with only three know examples that have been successfully commercialized.

  10. Taiwan's underwater cultural heritage documentation management

    Science.gov (United States)

    Tung, Y.-Y.

    2015-09-01

    Taiwan is an important trading and maritime channels for many countries since ancient time. Numerous relics lie underwater due to weather, wars, and other factors. In the year of 2006, Bureau of Cultural Heritage (BOCH) entrusted the Underwater Archaeological Team of Academia Sinica to execute the underwater archaeological investigation projects. Currently, we verified 78 underwater targets, with 78 site of those had been recognized as shipwrecks sites. Up to date, there is a collection of 638 underwater objects from different underwater archaeological sites. Those artefacts are distributed to different institutions and museums. As very diverse management methods/systems are applied for every individual institution, underwater cultural heritage data such as survey, excavation report, research, etc. are poorly organized and disseminated for use. For better communication regarding to Taiwan's underwater cultural heritage in every level, a universal format of documentation should be established. By comparing the existing checklist used in Taiwan with guidelines that are followed in other countries, a more intact and appropriate underwater cultural heritage condition documentation system can be established and adapted in Taiwan.

  11. Underwater inverse LIBS (iLIBS) for marine archaeology

    Science.gov (United States)

    Asmus, J.; Magde, M.; Elford, J.; Magde, D.; Parfenov, V.

    2013-05-01

    In recent years there have been enormous advances in nautical archaeology through developments in SONAR technologies as well as in manned and robotic submersible vehicles. The number of sunken vessel discoveries has escalated in many of the seas of the world in response to the widespread application of these and other new tools. Customarily, surviving artifacts within the debris field of a wreck are collected and then moved to laboratories, centers, or institutions for analyses and possible conservation. Frequently, the conservation phase involves chemical treatments to stabilize an artefact to standard temperature, pressure, and humidity instead of an undersea environment. Many of the artefacts encountered at an underwater site are now characterized and restored in-situ in accordance with modern trends in art conservation. Two examples of this trend are exemplified by the resting place of the wreck of the Titanic in the Atlantic and the Cancun Underwater Park in the Caribbean Sea. These two debris fields have been turned into museums for diving visitors. Several research groups have investigated the possibility of adapting the well-established analytical tool Laser Induced Breakdown Spectroscopy (LIBS) to in-situ elemental analyses of underwater cultural, historic, and archaeological artefacts where discovered, rather than as a phase of a salvage operation. As the underwater laser ablation associated with LIBS generates a "snowplough" shockwave within the aqueous matrix, the atomic emission spectrum is usually severely attenuated in escaping from the target. Consequently, probative experiments to date generally invoke a submerged air chamber or air jet to isolate water from the interaction zone as well as employ more complex double-pulse lasers. These measures impose severe logistical constraints on the examination of widely dispersed underwater artefacts. In order to overcome this constraint we report on water-immersion LIBS experiments performed with oblique

  12. Underwater Noise Pollution at the Strait of Istanbul (Bosphorus

    Directory of Open Access Journals (Sweden)

    Cem Gazioğlu

    2016-12-01

    Full Text Available Underwater noise pollution (UNP has become a major concern in marine habitats, which is intense anthropogenic noise in the marine (aquatic environment. It is caused by ship traffic, oceanographic experiments, and use of explosives in geophysical research, underwater construction, active sonars and seismic survey techniques. Oceans are much nosier than 1960s. Narrow and shallow channel noisy aquatic environments where noise levels reach the highest value is not surprising. The Strait of Istanbul (SoI; Bosphorus is one of the most important maritime passages (app. 50 000 vessel/year or 140 vessel/day which is situated between the Black Sea and the Aegean Sea are also biologically extremely important gateway not only it provides access to a channel. Many of the varieties of fish migration hunting value are realized through the TSS. Local maritime traffic is another important acoustic sources which are more than 3 000 elements (Kesgin and Vardar, 2001 of everyday local traffic in SoI, which are causing noise in the 2 and 10 kHz range. Large vessels create signals both in bands below 1 kHz (main engine, electrical instruments cavitation noise creates higher frequency bands. Almost all elements of marine traffic in SoI located therefore encountered UND in all bands.

  13. R and D Developments. Research Programs on Irradiation Embrittlement of Reactor Vessel Steels

    International Nuclear Information System (INIS)

    Gomez Briceno, D.; Lapena, J.; Serrano, M.; Perosanz, F.

    2000-01-01

    Irradiation embrittlement of pressure vessel steels is a degradation mechanism time dependent that can lead to operational restrictions with adverse effects in the efficiency and life of a plant. For the last year, several research programs have been devoted to study thye evaluation of neutronic radiation effect on mechanical properties of pressure vessel steels. However, at the present, there is a growing interest on the development of new methodologies to optimize the surveillance program information, and the understanding of the irradiation damage mechanism. This paper give an overview of international research programs, and on the R+D activities carried out by the Structural Materials Project on irradiation embrittlement on pressure vessel steels. (Author)

  14. Underwater research methods for study of nuclear bomb craters, Enewetak, Marshall Islands

    Science.gov (United States)

    Shinn, E.A.; Halley, R.B.; Kindinger, J.L.; Hudson, J.H.; Slate, R.A.

    1990-01-01

    Three craters, created by the explosion of nuclear fusion devices, were mapped, sampled, core drilled and excavated with airlifts at Enewetak Atoll in the Marshall Islands by using scuba and a research submersible. The craters studied were Mike, Oak, and Koa. Tests took place near sea level at the transition between lithified reef flat and unlithified lagoonal sediments, where water depth ranged from 1 to 4 m. Craters produced by the blasts ranged from 30 to 60 m in depth. The purpose of our study was to determine crater diameter and depth immediately after detonation. Observations of submerged roadways and testing structures and upturned crater rims similar to those characteristic of meteor impacts indicate that the initial, or transient, craters were smaller than their present size. At some later time, while the area was too radioactive for direct examination, the sides of the craters slumped owing to dewatering of under lying pulverized rock. Core drilling of crater margins with a diver-operated hydraulic coring device provided additional data. On the seaward margin of the atoll, opposite Mike, a large portion of the atoll rim approximately the size of a city block had slumped into the deep ocean, leaving a clean vertical rock section more than 400m high. An abundance of aggressive grey reef sharks displaying classic territorial behavior prevented use of scuba at the Mike slump site. The two-person submersible R.V. Delta provided protection and allowed observations down to 300 m. During the 6-week period of study, we made more than 300 scuba and 275 submersible dives. Mapping was with side scan sonar and continuous video sweeps supplemented by tape-recorded verbal descriptions made from within the submersible. A mini-ranger navigation system linked to the submersible allowed plotting of bottom features, depth and sediment type with spatial accuracy to within 2 m.

  15. Concept of a nuclear powered submersible research vessel and a compact reactor

    International Nuclear Information System (INIS)

    Kusunoki, Tsuyoshi; Odano, Naoteru; Yoritsune, Tsutomu; Ishida, Toshihisa; Nishimura, Hajime; Tokunaga, Sango

    2001-07-01

    A conceptual design study of a submersible research vessel navigating in 600 m depth and a compact nuclear reactor were carried out for the expansion of the nuclear power utilization. The mission of the vessel is the research of mechanism of the climate change to predict the global environment. Through conditions of the Arctic Ocean and the sea at high latitude have significant impacts on the global environmental change, it is difficult to investigate those areas by ordinary ships because of thick ice or storm. Therefore the research vessel is mainly utilized in the Arctic Ocean and the sea at high latitude. By taking account of the research mission, the basic specifications of the vessel are decided; the total weight is 500 t, the submersible depth is 600 m, the maximum speed is 12 knots (22.2 km/h), and the number of crews is 16. Nuclear power has an advantage in supplying large power of electricity in the sea for long period. Based on the requirements, it has been decided that two sets of submersible compact reactor, SCR, which is light-weighted and of enhanced safety characteristics of supply the total electricity of 500 kW. (author)

  16. Underwater Sediment Sampling Research

    Science.gov (United States)

    2017-01-01

    impacted sediments was found to be directly related to the concentration of crude oil detected in the sediment pore waters . Applying this mathematical...Kurt.A.Hansen@uscg.mil. 16. Abstract (MAXIMUM 200 WORDS ) The USCG R&D Center sought to develop a bench top system to determine the amount of total...scattered. The approach here is to sample the interstitial water between the grains of sand and attempt to determine the amount of oil in and on

  17. Underwater laser cutting of metallic structures

    International Nuclear Information System (INIS)

    Alfille, J.P.; Schildknecht, J.; Ramaswami, V.S.

    1993-01-01

    In the frame of an european contract, the feasibility of the underwater cutting with a CO 2 laser power is studied. The aim of this work is the dismantling metallic structures of reactors pools. The paper analyzes the general concept of the experimental device, the underwater cutting head, the experimenting vessel, examples of cuttings in dismantling situation with a 500 W CO 2 laser, and examples of cuttings with a 5 kW CO 2 laser. (author). 2 refs., 9 figs., 2 tabs

  18. The Support of Underwater Works with the Use of Remotely Operated Vehicles On the Example of Works Conducted On the Wreck of the Fishing Boat WŁA-127

    Directory of Open Access Journals (Sweden)

    Dawidziuk Marek

    2017-03-01

    Full Text Available The article demonstrates use of underwater remotely operated vehicles during an underwater visual inspection of a sunken vessel. The presented tasks were carried out in the course of underwater works performed from a Polish navy rescue vessel on the fishing boat WŁA-127. The discussed examples include a visual inspection of the sunken vessel and the support offered to Polish Navy rescue divers as they carried out underwater works.

  19. Flow around an autonomous underwater vehicle with bio-inspired coating

    Science.gov (United States)

    Watkins, Scott; Montoya-Segnini, Jose; Bocanegra Evans, Humberto; Curet, Oscar; Gorumlu, Serdar; Aksak, Burak; Kazemi, Amirkhosro; Chamorro, Leonardo; Castillo, Luciano

    2017-11-01

    Flow separation plays a major factor in the form drag of a moving object. In particular, suppressing or reducing flow separation is critical in the energy expenditure of autonomous underwater vehicles. Previous research suggests that bio-inspired micro-fibrillar structures are capable of reducing the boundary layer separation in a turbulent flow. Here, we present laboratory measurements using PIV near the wall and in the wake of two submersible vessel models; one had a coating composed of ordered fibers, and the other had smooth walls. Flow characterization with planar PIV included the presence or absence of a tail fin at multiple angles of attack of the vessels. Preliminary results reveal changes of the flow in the wake of the vessel with coating resulting in lower or similar velocity deficit in the wake compared to the smooth vessel.

  20. Reactor pressure vessel steels[1997 Scientific Report of the Belgian Nuclear Research Centre

    Energy Technology Data Exchange (ETDEWEB)

    Van De Velde, J.; Fabry, A.; Van Walle, E.; Chaouuadi, R.

    1998-07-01

    Research and development activities related to reactor pressure vessel steels during 1997 are reported. The objectives of activities of the Belgian Nuclear Research Centre SCK/CEN in this domain are: (1) to develop enhanced surveillance concepts by applying micromechanics and fracture-toughness tests to small specimens, and by performing damage modelling and microstructure characterization; (2) to demonstrate a methodology on a broad database; (3) to achieve regulatory acceptance and industrial use.

  1. Survivability design for a hybrid underwater vehicle

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Biao; Wu, Chao; Li, Xiang; Zhao, Qingkai; Ge, Tong [State Key Lab of Ocean Engineering, School of Naval Architecture, Ocean and Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2015-03-10

    A novel hybrid underwater robotic vehicle (HROV) capable of working to the full ocean depth has been developed. The battery powered vehicle operates in two modes: operate as an untethered autonomous vehicle in autonomous underwater vehicle (AUV) mode and operate under remote control connected to the surface vessel by a lightweight, fiber optic tether in remotely operated vehicle (ROV) mode. Considering the hazardous underwater environment at the limiting depth and the hybrid operating modes, survivability has been placed on an equal level with the other design attributes of the HROV since the beginning of the project. This paper reports the survivability design elements for the HROV including basic vehicle design of integrated navigation and integrated communication, emergency recovery strategy, distributed architecture, redundant bus, dual battery package, emergency jettison system and self-repairing control system.

  2. Survivability design for a hybrid underwater vehicle

    International Nuclear Information System (INIS)

    Wang, Biao; Wu, Chao; Li, Xiang; Zhao, Qingkai; Ge, Tong

    2015-01-01

    A novel hybrid underwater robotic vehicle (HROV) capable of working to the full ocean depth has been developed. The battery powered vehicle operates in two modes: operate as an untethered autonomous vehicle in autonomous underwater vehicle (AUV) mode and operate under remote control connected to the surface vessel by a lightweight, fiber optic tether in remotely operated vehicle (ROV) mode. Considering the hazardous underwater environment at the limiting depth and the hybrid operating modes, survivability has been placed on an equal level with the other design attributes of the HROV since the beginning of the project. This paper reports the survivability design elements for the HROV including basic vehicle design of integrated navigation and integrated communication, emergency recovery strategy, distributed architecture, redundant bus, dual battery package, emergency jettison system and self-repairing control system

  3. 4th Pacific Rim Underwater Acoustics Conference

    CERN Document Server

    Xu, Wen; Cheng, Qianliu; Zhao, Hangfang

    2016-01-01

    These proceedings are a collection of 16 selected scientific papers and reviews by distinguished international experts that were presented at the 4th Pacific Rim Underwater Acoustics Conference (PRUAC), held in Hangzhou, China in October 2013. The topics discussed at the conference include internal wave observation and prediction; environmental uncertainty and coupling to sound propagation; environmental noise and ocean dynamics; dynamic modeling in acoustic fields; acoustic tomography and ocean parameter estimation; time reversal and matched field processing; underwater acoustic localization and communication as well as measurement instrumentations and platforms. These proceedings provide insights into the latest developments in underwater acoustics, promoting the exchange of ideas for the benefit of future research.

  4. Blind equalization for underwater communications

    NARCIS (Netherlands)

    Blom, K.C.H.

    2014-01-01

    Underwater wireless (sensor) networks would vastly improve man's ability to explore and exploit remote aquatic environments. Despite underwater sensor and vehicle technology being relatively mature, underwater communications is still a major challenge. The most challenging characteristics of the

  5. Applying the TOC Project Management to Operation and Maintenance Scheduling of a Research Vessel

    Science.gov (United States)

    Manti, M. Firdausi; Fujimoto, Hideo; Chen, Lian-Yi

    Marine research vessels and their systems are major assets in the marine resources development. Since the running costs for the ship are very high, it is necessary to reduce the total cost by an efficient scheduling for operation and maintenance. To reduce project period and make it efficient, we applied TOC project management method that is a project management approach developed by Dr. Eli Goldratt. It challenges traditional approaches to project management. It will become the most important improvement in the project management since the development of PERT and critical path methodologies. As a case study, we presented the marine geology research project for the purpose of operations in addition to repair on the repairing dock projects for maintenance of vessels.

  6. An innovative methodology for the transmission of information, using Sensor Web Enablement, from ongoing research vessels.

    Science.gov (United States)

    Sorribas, Jordi; Sinquin, Jean Marc; Diviacco, Paolo; De Cauwer, Karien; Danobeitia, Juanjo; Olive, Joan; Bermudez, Luis

    2013-04-01

    Research vessels are sophisticated laboratories with complex data acquisition systems for a variety of instruments and sensors that acquire real-time information of many different parameters and disciplines. The overall data and metadata acquired commonly spread using well-established standards for data centers; however, the instruments and systems on board are not always well described and it may miss significant information. Thus, important information such as instrument calibration or operational data often does not reach to the data center. The OGC Sensor Web Enablement standards provide solutions to serve complex data along with the detailed description of the process used to obtain them. We show an innovative methodology on how to use Sensor Web Enablement standards to describe and serve information from the research vessels, the data acquisition systems used onboard, and data sets resulting from the onboard work. This methodology is designed to be used in research vessels, but also applies to data centers to avoid loss of information in between The proposed solution considers (I) the difficulty to describe a multidisciplinary and complex mobile sensor system, (II) it can be easily integrated with data acquisition systems onboard, (III) it uses the complex and incomplete typical vocabulary in marine disciplines, (IV) it provides contacts with the data and metadata services at the Data Centers, and (V) it manages the configuration changes with time of the instrument.

  7. Summary of the guideline on underwater laser beam repair welding

    International Nuclear Information System (INIS)

    Ichikawa, Hiroya; Yoda, Masaki; Motora, Yuichi

    2013-01-01

    It is known that stress corrosion cracking (SCC) might occur at the weld of a reactor pressure vessel or core internals. Underwater laser beam clad welding for mitigation of SCC has been already established and the guideline 'Underwater laser beam clad welding' was published. Moreover, the guideline 'Seal welding' was also published as a repair method for SCC. In addition to these guidelines, the guideline 'Underwater laser beam repair welding' was newly published in November, 2012 for the repair welding after completely removing a SCC crack occurred in weld or base metal. This paper introduces the summary of this guideline. (author)

  8. Safety Research Experiment Facility Project. Conceptual design report. Volume V. Reactor vessel and closure

    International Nuclear Information System (INIS)

    1975-12-01

    The Prestressed Concrete Reactor Vessel (PCRV) will serve as the primary pressure retaining structure for the Safety Research Experiment Facility (SAREF) reactor. The reactor core, control rod drive room, primary heat exchangers, and gas circulators will be located in cavities within the PCRV. The orientation of these cavities, except for the control rod drive room, will be similar to the high-temperature gas-cooled reactor (HTGR) designs that are currently proposed or under design. Due to the nature of this type of structure, all biological and radiological shielding requirements are incorporated into the basic vessel design. At the midcore plane there are three radially oriented slots that will extend from the outside surface of the PCRV to the reactor core liner. These slots will accommodate each of the fuel motion monitoring systems which will be part of the observation apparatus used with the loop experiments

  9. Underwater Scene Composition

    Science.gov (United States)

    Kim, Nanyoung

    2009-01-01

    In this article, the author describes an underwater scene composition for elementary-education majors. This project deals with watercolor with crayon or oil-pastel resist (medium); the beauty of nature represented by fish in the underwater scene (theme); texture and pattern (design elements); drawing simple forms (drawing skill); and composition…

  10. Underwater Acoustic Networking Techniques

    CERN Document Server

    Otnes, Roald; Casari, Paolo; Goetz, Michael; Husøy, Thor; Nissen, Ivor; Rimstad, Knut; van Walree, Paul; Zorzi, Michele

    2012-01-01

    This literature study presents an overview of underwater acoustic networking. It provides a background and describes the state of the art of all networking facets that are relevant for underwater applications. This report serves both as an introduction to the subject and as a summary of existing protocols, providing support and inspiration for the development of network architectures.

  11. Underwater Acoustic Tracer System

    Science.gov (United States)

    2009-03-13

    for controlling and utilizing supercavitating projectile dynamics to produce a distinctive radiated noise signal. (2) Description of the Prior Art...metallic objects which travel relatively closely to a magnetic pickup. For larger, high speed, underwater projectiles, supercavitating underwater vehicles...have been proposed for use. The conditions for supercavitation are known in the art. Supercavitation allows for higher speeds to be sustainable

  12. Modeling and Control of Underwater Robotic Systems

    Energy Technology Data Exchange (ETDEWEB)

    Schjoelberg, I:

    1996-12-31

    This doctoral thesis describes modeling and control of underwater vehicle-manipulator systems. The thesis also presents a model and a control scheme for a system consisting of a surface vessel connected to an underwater robotic system by means of a slender marine structure. The equations of motion of the underwater vehicle and manipulator are described and the system kinematics and properties presented. Feedback linearization technique is applied to the system and evaluated through a simulation study. Passivity-based controllers for vehicle and manipulator control are presented. Stability of the closed loop system is proved and simulation results are given. The equation of motion for lateral motion of a cable/riser system connected to a surface vessel at the top end and to a thruster at the bottom end is described and stability analysis and simulations are presented. The equations of motion in 3 degrees of freedom of the cable/riser, surface vessel and robotic system are given. Stability analysis of the total system with PD-controllers is presented. 47 refs., 32 figs., 7 tabs.

  13. Stability analysis of hybrid-driven underwater glider

    Science.gov (United States)

    Niu, Wen-dong; Wang, Shu-xin; Wang, Yan-hui; Song, Yang; Zhu, Ya-qiang

    2017-10-01

    Hybrid-driven underwater glider is a new type of unmanned underwater vehicle, which combines the advantages of autonomous underwater vehicles and traditional underwater gliders. The autonomous underwater vehicles have good maneuverability and can travel with a high speed, while the traditional underwater gliders are highlighted by low power consumption, long voyage, long endurance and good stealth characteristics. The hybrid-driven underwater gliders can realize variable motion profiles by their own buoyancy-driven and propeller propulsion systems. Stability of the mechanical system determines the performance of the system. In this paper, the Petrel-II hybrid-driven underwater glider developed by Tianjin University is selected as the research object and the stability of hybrid-driven underwater glider unitedly controlled by buoyancy and propeller has been targeted and evidenced. The dimensionless equations of the hybrid-driven underwater glider are obtained when the propeller is working. Then, the steady speed and steady glide path angle under steady-state motion have also been achieved. The steady-state operating conditions can be calculated when the hybrid-driven underwater glider reaches the desired steady-state motion. And the steadystate operating conditions are relatively conservative at the lower bound of the velocity range compared with the range of the velocity derived from the method of the composite Lyapunov function. By calculating the hydrodynamic coefficients of the Petrel-II hybrid-driven underwater glider, the simulation analysis has been conducted. In addition, the results of the field trials conducted in the South China Sea and the Danjiangkou Reservoir of China have been presented to illustrate the validity of the analysis and simulation, and to show the feasibility of the method of the composite Lyapunov function which verifies the stability of the Petrel-II hybrid-driven underwater glider.

  14. Measurement and flow visualization research of thermal hydraulic characteristics for the SFR reactor Vessel

    International Nuclear Information System (INIS)

    Cha, J. E.; Kim, S. O.; Choi, H. L.; Kim, H. B.; Kim, H. W.; Lee, S. H.

    2012-01-01

    In this report, the thermal hydraulic and flow visualization experiment was described for the KALIMER-600 water-scaled model. In order to investigate a thermal hydraulic characteristics for the SFR KALIMER-600, which has been conceptually designed in the KAERI, a water-scaled 1/10 reactor vessel model was designed and prepared through the scaling analysis during three-years research. In this research, SFR Photos system, which has inherently very complicated the internal structures, was fabricated with a transparent vessel. It was shown that a serious of thermal hydraulic test was conducted within a short period if modeled with water than sodium. Natural circulation test was successfully performed with the modeled heater assembly and heat exchanger system coupled with cooling system. The water-scaled RSV experimental facility made in this research could be used to study the USA development for the future SFR system and utilized to analyze the flow characteristics before changing a main internal part of Photos system. It could also be used to test a pool-inspection study and a sensor selection study before large scale sodium experiment. The PCV system prepared in this research could be utilized to test other TSH experiment and temperature field measurement

  15. Design of underwater work systems

    International Nuclear Information System (INIS)

    Lovelace, R.B.

    1980-01-01

    In the near future, underwater vehicles will replace divers as the principal means for inspection and maintenance work. These vehicles will provide a maneuverable work platform for an underwater viewing system and manipulator/tool package. Some of the problems faced by the underwater designer, and some areas to consider in the design of an integrated underwater work system, are considered

  16. Data Collected in 1959 by English Research Vessels at Serial and Surface Hydrographic Stations (NODC Accession 6900852)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The present volume contains data collected in 1959 by English research vessels at serial and surface hydrographic stations. The data list are preceded by a number of...

  17. CTD Data from Research Vessel New Horizon in the NE Pacific, 24 April - 01 May 2014 (NCEI Accession 0157699)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Two consecutive expeditions by research vessel New Horizon in April/May 2014 (NH1408 and NH1409) had the objective to recover and re-deploy a number of moored...

  18. CTD Data from Research Vessel New Horizon in the NE Pacific, 15-20 December 2009 (NCEI Accession 0156689)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The expedition by research vessel New Horizon from 15 to 20 December 2009 had the objective to recover and re-deploy a number of moored platforms off southern...

  19. Delay Tolerance in Underwater Wireless Communications: A Routing Perspective

    Directory of Open Access Journals (Sweden)

    Safdar Hussain Bouk

    2016-01-01

    Full Text Available Similar to terrestrial networks, underwater wireless networks (UWNs also aid several critical tasks including coastal surveillance, underwater pollution detection, and other maritime applications. Currently, once underwater sensor nodes are deployed at different levels of the sea, it is nearly impossible or very expensive to reconfigure the hardware, for example, battery. Taking this issue into account, considerable amount of research has been carried out to ensure minimum energy costs and reliable communication between underwater nodes and base stations. As a result, several different network protocols were proposed for UWN, including MAC, PHY, transport, and routing. Recently, a new paradigm was introduced claiming that the intermittent nature of acoustic channel and signal resulted in designing delay tolerant routing schemes for the UWN, known as an underwater delay tolerant network. In this paper, we provide a comprehensive survey of underwater routing protocols with emphasis on the limitations, challenges, and future open issues in the context of delay tolerant network routing.

  20. The instrumentation of the prestressed concrete vessel with hot liner at Seibersdorf Research Centre

    International Nuclear Information System (INIS)

    Zemann, H.

    1975-11-01

    The joint project ''Prestressed Concrete Pressure Vessel with Hot Liner'' at Seibersdorf Research Centre now is in the process of testing the PCPV both in construction and operation from the safety point of view. The physical state of the PCPV (modulus of elasticity, humidity of concrete, creeping, etc.) is brought to stable conditions by ''pre-aging''. In order to control this process of stabilisation, an extensive knowledge of the concrete and an elaborated instrumentation is a necessity. This paper presents a survey about the philosophy and the realisation of the instrumentation of the PCPV and the investigations we performed to interpret the measurements. (author)

  1. 3D Laser Scanner for Underwater Manipulation

    Directory of Open Access Journals (Sweden)

    Albert Palomer

    2018-04-01

    Full Text Available Nowadays, research in autonomous underwater manipulation has demonstrated simple applications like picking an object from the sea floor, turning a valve or plugging and unplugging a connector. These are fairly simple tasks compared with those already demonstrated by the mobile robotics community, which include, among others, safe arm motion within areas populated with a priori unknown obstacles or the recognition and location of objects based on their 3D model to grasp them. Kinect-like 3D sensors have contributed significantly to the advance of mobile manipulation providing 3D sensing capabilities in real-time at low cost. Unfortunately, the underwater robotics community is lacking a 3D sensor with similar capabilities to provide rich 3D information of the work space. In this paper, we present a new underwater 3D laser scanner and demonstrate its capabilities for underwater manipulation. In order to use this sensor in conjunction with manipulators, a calibration method to find the relative position between the manipulator and the 3D laser scanner is presented. Then, two different advanced underwater manipulation tasks beyond the state of the art are demonstrated using two different manipulation systems. First, an eight Degrees of Freedom (DoF fixed-base manipulator system is used to demonstrate arm motion within a work space populated with a priori unknown fixed obstacles. Next, an eight DoF free floating Underwater Vehicle-Manipulator System (UVMS is used to autonomously grasp an object from the bottom of a water tank.

  2. 3D Laser Scanner for Underwater Manipulation.

    Science.gov (United States)

    Palomer, Albert; Ridao, Pere; Youakim, Dina; Ribas, David; Forest, Josep; Petillot, Yvan

    2018-04-04

    Nowadays, research in autonomous underwater manipulation has demonstrated simple applications like picking an object from the sea floor, turning a valve or plugging and unplugging a connector. These are fairly simple tasks compared with those already demonstrated by the mobile robotics community, which include, among others, safe arm motion within areas populated with a priori unknown obstacles or the recognition and location of objects based on their 3D model to grasp them. Kinect-like 3D sensors have contributed significantly to the advance of mobile manipulation providing 3D sensing capabilities in real-time at low cost. Unfortunately, the underwater robotics community is lacking a 3D sensor with similar capabilities to provide rich 3D information of the work space. In this paper, we present a new underwater 3D laser scanner and demonstrate its capabilities for underwater manipulation. In order to use this sensor in conjunction with manipulators, a calibration method to find the relative position between the manipulator and the 3D laser scanner is presented. Then, two different advanced underwater manipulation tasks beyond the state of the art are demonstrated using two different manipulation systems. First, an eight Degrees of Freedom (DoF) fixed-base manipulator system is used to demonstrate arm motion within a work space populated with a priori unknown fixed obstacles. Next, an eight DoF free floating Underwater Vehicle-Manipulator System (UVMS) is used to autonomously grasp an object from the bottom of a water tank.

  3. Cooperative OFDM underwater acoustic communications

    CERN Document Server

    Cheng, Xilin; Cheng, Xiang

    2016-01-01

    Following underwater acoustic channel modeling, this book investigates the relationship between coherence time and transmission distances. It considers the power allocation issues of two typical transmission scenarios, namely short-range transmission and medium-long range transmission. For the former scenario, an adaptive system is developed based on instantaneous channel state information. The primary focus is on cooperative dual-hop orthogonal frequency division multiplexing (OFDM). This book includes the decomposed fountain codes designed to enable reliable communications with higher energy efficiency. It covers the Doppler Effect, which improves packet transmission reliability for effective low-complexity mirror-mapping-based intercarrier interference cancellation schemes capable of suppressing the intercarrier interference power level. Designed for professionals and researchers in the field of underwater acoustic communications, this book is also suitable for advanced-level students in electrical enginee...

  4. International Conference on Underwater Environment

    CERN Document Server

    Jaulin, Luc; Creuze, Vincent; Debese, Nathalie; Quidu, Isabelle; Clement, Benoît; Billon-Coat, Annick

    2016-01-01

    This volume constitutes the results of the International Conference on Underwater Environment, MOQESM’14, held at “Le Quartz” Conference Center in Brest, France, on October 14-15, 2014, within the framework of the 9th Sea Tech Week, International Marine Science and Technology Event. The objective of MOQESM'14 was to bring together researchers from both academia and industry, interested in marine robotics and hydrography with application to the coastal environment mapping and underwater infrastructures surveys. The common thread of the conference is the combination of technical control, perception, and localization, typically used in robotics, with the methods of mapping and bathymetry. The papers presented in this book focus on two main topics. Firstly, coastal and infrastructure mapping is addressed, focusing not only on hydrographic systems, but also on positioning systems, bathymetry, and remote sensing. The proposed methods rely on acoustic sensors such as side scan sonars, multibeam echo sounders, ...

  5. Research on release rate of volatile organic compounds in typical vessel cabin

    Directory of Open Access Journals (Sweden)

    ZHANG Jinlan

    2018-02-01

    Full Text Available [Objectives] Volatile Organic Compounds (VOC should be efficiently controlled in vessel cabins to ensure the crew's health and navigation safety. As an important parameter, research on release rate of VOCs in cabins is required. [Methods] This paper develops a method to investigate this parameter of a ship's cabin based on methods used in other closed indoor environments. A typical vessel cabin is sampled with Tenax TA tubes and analyzed by Automated Thermal Desorption-Gas Chromatography-Mass Spectrometry (ATD-GC/MS. The lumped mode is used and the release rate of Benzene, Toluene, Ethylbenzene and Xylene (BTEX, the typical representatives of VOCs, is obtained both in closed and ventilated conditions. [Results] The results show that the content of xylene and Total Volatile Organic Compounds (TVOC exceed the indoor environment standards in ventilated conditions. The BTEX release rate is similar in both conditions except for the benzene. [Conclusions] This research builds a method to measure the release rate of VOCs, providing references for pollution character evaluation and ventilation and purification system design.

  6. Ocean Wave Energy: Underwater Substation System for Wave Energy Converters

    International Nuclear Information System (INIS)

    Rahm, Magnus

    2010-01-01

    This thesis deals with a system for operation of directly driven offshore wave energy converters. The work that has been carried out includes laboratory testing of a permanent magnet linear generator, wave energy converter mechanical design and offshore testing, and finally design, implementation, and offshore testing of an underwater collector substation. Long-term testing of a single point absorber, which was installed in March 2006, has been performed in real ocean waves in linear and in non-linear damping mode. The two different damping modes were realized by, first, a resistive load, and second, a rectifier with voltage smoothing capacitors and a resistive load in the DC-link. The loads are placed on land about 2 km east of the Lysekil wave energy research site, where the offshore experiments have been conducted. In the spring of 2009, another two wave energy converter prototypes were installed. Records of array operation were taken with two and three devices in the array. With two units, non-linear damping was used, and with three units, linear damping was employed. The point absorbers in the array are connected to the underwater substation, which is based on a 3 m3 pressure vessel standing on the seabed. In the substation, rectification of the frequency and amplitude modulated voltages from the linear generators is made. The DC voltage is smoothened by capacitors and inverted to 50 Hz electrical frequency, transformed and finally transmitted to the on-shore measuring station. Results show that the absorption is heavily dependent on the damping. It has also been shown that by increasing the damping, the standard deviation of electrical power can be reduced. The standard deviation of electrical power is reduced by array operation compared to single unit operation. Ongoing and future work include the construction and installation of a second underwater substation, which will connect the first substation and seven new WECs

  7. Underwater wireless communication system

    International Nuclear Information System (INIS)

    Goh, J H; Shaw, A; Al-Shamma'a, A I

    2009-01-01

    Underwater communication has a range of applications including remotely operated vehicle (ROV) and autonomous underwater vehicle (AUV) communication and docking in the offshore industry. Current underwater transmission techniques is primarily utilise sound waves for large distance at lower frequencies and the velocity of sound in water is approximately 1500m/s the resultant communications have problems with multi-path propagation and low bandwidth problems. The use of electromagnetic (EM) techniques underwater has largely been overlooked because of the attenuation due to the conductivity of seawater. However, for short range applications, the higher frequencies and much higher velocity can prove advantageous. This paper will outline a project which will utilise recent investigations that demonstrate EM wave propagation up to the MHz frequency range is possible in seawater.

  8. Smelling and Tasting Underwater.

    Science.gov (United States)

    Atema, Jelle

    1980-01-01

    Discusses differences between smell and taste, comparing these senses in organisms in aquatic and terrestrial environments. Describes the chemical environment underwater and in air, differences in chemoreceptors to receive stimuli, and the organs, brain, and behavior involved in chemoreception. (CS)

  9. Autonomous Underwater Gliders

    OpenAIRE

    Wood,; Stephen,

    2009-01-01

    Autonomous Underwater Vehicles are only now being marketed as robust commercial vehicles for many industries, and of these vehicles underwater gliders are becoming the new tool for oceanographers. Satellites have provided scientists and marine specialists with measurements of the sea surface such as temperature since the late 1970s, and data via subsurface oceanographic moorings since the 1950's. As stated by David Smeed of the National Oceanography Centre, Southampton, England, that "gliders...

  10. Research towards ultrasonic systems to assist in-vessel manipulations in liquid metal cooled reactors

    International Nuclear Information System (INIS)

    Dierckx, Marc; Van-Dyck, Dries

    2013-06-01

    We describe the state of the art of the research towards ultrasonic measurement methods for use in lead-bismuth cooled liquid metal reactors. Our current research activities are highly focused on specific tasks in the MYRRHA system, which is a fast spectrum research reactor cooled with the eutectic mixture of lead and bismuth (LBE) and is conceived as an accelerator driven system capable of operating in both sub-critical and critical mode. As liquid metal is opaque to light, normal visual feedback during fuel manipulations in the reactor vessel is not available and must therefore be replaced by a system that is not hindered by the opacity of the coolant. In this respect ultrasonic measurement techniques have been proposed and even developed in the past for operation in sodium cooled reactors. To our knowledge, no such systems have ever been deployed in lead based reactors and we are the first to have a research program in this direction as will be detailed in this paper. We give an overview of the acoustic properties of LBE and compare them with the properties of sodium and water to theoretically show the feasibility of ultrasonic systems operating in LBE. In the second part of the paper we discuss the results of the validation experiments in water and LBE. A typical scene is ultrasonically probed by a mechanical scanning system while the signals are processed to render a 3D visualization on a computer screen. It will become clear that mechanical scanning is capable of producing acceptable images but that it is a time consuming process that is not fit to solve the initial task to providing feedback during manipulations in the reactor vessel. That is why we propose to use several dedicated ultrasonic systems each adapted to a specific task and capable to provide real-time feedback of the ongoing manipulations, as is detailed in the third and final part of the paper. (authors)

  11. Mini neutron monitor measurements at the Neumayer III station and on the German research vessel Polarstern

    Science.gov (United States)

    Heber, B.; Galsdorf, D.; Herbst, K.; Gieseler, J.; Labrenz, J.; Schwerdt, C.; Walter, M.; Benadé, G.; Fuchs, R.; Krüger, H.; Moraal, H.

    2015-08-01

    Neutron monitors (NMs) are ground-based devices to measure the variation of cosmic ray intensities, and although being reliable they have two disadvantages: their size as well as their weight. As consequence, [1] suggested the development of a portable, and thus much smaller and lighter, calibration neutron monitor that can be carried to any existing station around the world [see 2; 3]. But this mini neutron monitor, moreover, can also be installed as an autonomous station at any location that provides ’’office” conditions such as a) temperatures within the range of around 0 to less than 40 degree C as well as b) internet and c) power supply. However, the best location is when the material above the NM is minimized. In 2011 a mini Neutron Monitor was installed at the Neumayer III station in Antarctica as well as the German research vessel Polarstern, providing scientific data since January 2014 and October 2012, respectively. The Polarstern, which is in the possession of the Federal Republic of Germany represented by the Ministry of Education and Research and operated by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research and managed by the shipping company Laeisz, was specially designed for working in the polar seas and is currently one of the most sophisticated polar research vessels worldwide. It spends almost 310 days a year at sea usually being located in the waters of Antarctica between November and March while spending the northern summer months in Arctic waters. Therefore, the vessel scans the rigidity range below the atmospheric threshold and above 10 GV twice a year. In contrast to spacecraft measurements NM data are influenced by variations of the geomagnetic field as well as the atmospheric conditions. Thus, in order to interpret the data a detailed knowledge of the instrument sensitivity with geomagnetic latitude (rigidity) and atmospheric pressure is essential. In order to determine the atmospheric response data from the

  12. Mini neutron monitor measurements at the Neumayer III station and on the German research vessel Polarstern

    International Nuclear Information System (INIS)

    Heber, B; Galsdorf, D; Herbst, K; Gieseler, J; Labrenz, J; Schwerdt, C; Walter, M; Benadé, G; Fuchs, R; Krüger, H; Moraal, H

    2015-01-01

    Neutron monitors (NMs) are ground-based devices to measure the variation of cosmic ray intensities, and although being reliable they have two disadvantages: their size as well as their weight. As consequence, [1] suggested the development of a portable, and thus much smaller and lighter, calibration neutron monitor that can be carried to any existing station around the world [see 2; 3]. But this mini neutron monitor, moreover, can also be installed as an autonomous station at any location that provides ’’office” conditions such as a) temperatures within the range of around 0 to less than 40 degree C as well as b) internet and c) power supply. However, the best location is when the material above the NM is minimized. In 2011 a mini Neutron Monitor was installed at the Neumayer III station in Antarctica as well as the German research vessel Polarstern, providing scientific data since January 2014 and October 2012, respectively. The Polarstern, which is in the possession of the Federal Republic of Germany represented by the Ministry of Education and Research and operated by the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research and managed by the shipping company Laeisz, was specially designed for working in the polar seas and is currently one of the most sophisticated polar research vessels worldwide. It spends almost 310 days a year at sea usually being located in the waters of Antarctica between November and March while spending the northern summer months in Arctic waters. Therefore, the vessel scans the rigidity range below the atmospheric threshold and above 10 GV twice a year. In contrast to spacecraft measurements NM data are influenced by variations of the geomagnetic field as well as the atmospheric conditions. Thus, in order to interpret the data a detailed knowledge of the instrument sensitivity with geomagnetic latitude (rigidity) and atmospheric pressure is essential. In order to determine the atmospheric response data from the

  13. Neutron monitor measurements on the German research vessel Polarstern. First results

    Energy Technology Data Exchange (ETDEWEB)

    Heber, B. [Insititut fuer Experimentelle und Angewandte Physik, Christian-Albrechts-Universitaet zu Kiel (Germany); Schwerdt, C.; Walter, M. [Deutsches Elektronen-Synchrotron DESY, D-15738 Zeuthen (Germany); Bernade, G.; Fuchs, R.; Krueger, H.; Moraal, H. [Center for Space Research, North-West University, Potchefstroom 2520 (South Africa)

    2014-07-01

    Cosmic-ray particles provide a unique opportunity to probe the dynamic conditions in the highly variable heliosphere. The longest continuous measurements of galactic cosmic rays come from cosmogenic isotopes and from neutron monitors located at different location on Earth. Understanding the effects of energetic particles in and on the atmosphere and the environment of Earth must address their transport to Earth and their interactions with the Earth's atmosphere, including their filtering by the terrestrial magnetosphere. Since neutron monitors are integral detectors of secondary cosmic rays produced in the atmosphere, a single neutron monitor can only derive the energy spectra of the particles impinging on the Earth during latitudinal surveys. A portable neutron monitor was built at the North-West University, South Africa, and was installed on the German research vessel Polarstern. Such latitude surveys have been done before, but this vessel is better suited for this purpose than previous platforms because it traverses all the locations with geomagnetic cutoff rigidities from <<1 GV to 15 GV at least twice per year. In this contribution we present first results from the measurement campaigns.

  14. Improvement of shipborne sky radiometer and its demonstration aboard the Antarctic research vessel Shirase

    Directory of Open Access Journals (Sweden)

    Noriaki Tanaka

    2014-11-01

    Full Text Available The sun-tracking performance of a shipborne sky radiometer was improved to attain accurate aerosol optical thickness (AOT from direct solar measurements on a pitching and rolling vessel. Improvements were made in the accuracy of sun-pointing measurements, field-of-view expansion, sun-tracking speed, and measurement method. Radiometric measurements of direct solar and sky brightness distribution were performed using the shipborne sky radiometer onboard the Antarctic research vessel (R/V Shirase during JARE-51 (2009-2010 and JARE-52 (2010-2011. The temporal variation of signal intensity measured by the radiometer under cloudless conditions was smooth, demonstrating that the radiometer could measure direct sunlight onboard the R/V. AOT at 500 nm ranged from 0.01 to 0.34, and values over Southeast Asia and over the western Pacific Ocean in spring were higher than those over other regions. The Angstrom exponent ranged from -0.06 to 2.00, and values over Southeast Asia and off the coast near Sydney were the highest. The improved shipborne sky radiometer will contribute to a good understanding of the nature of aerosols over the ocean.

  15. Development of underwater laser cladding and underwater laser seal welding techniques for reactor components

    International Nuclear Information System (INIS)

    Hino, Takehisa; Tamura, Masataka; Tanaka, Yoshimi; Kouno, Wataru; Makino, Yoshinobu; Kawano, Shohei; Matsunaga, Keiji

    2009-01-01

    Stress corrosion cracking (SCC) has been reported at the aged components in many nuclear power plants. Toshiba has been developing the underwater laser welding. This welding technique can be conducted without draining the water in the reactor vessel. It is beneficial for workers not to exposure the radiation. The welding speed can be attaining twice as fast as that of Gas Tungsten Arc Welding (GTAW). The susceptibility of SCC can also be lower than the Alloy 600 base metal. (author)

  16. Reactor pressure vessel integrity research at the Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Corwin, W.R.; Pennell, W.E.; Pace, J.V.

    1995-01-01

    Maintaining the integrity of the reactor pressure vessel (RPV) in a light-water-cooled nuclear power plant is crucial in preventing and controlling severe accidents that have the potential for major contamination release. The RPV is the only key safety-related component of the plant for which a duplicate or redundant backup system does not exist. It is therefore imperative to understand and be able to predict the integrity inherent in the RPV. For this reason, the U.S. Nuclear Regulatory Commission has established the related research programs at ORNL described herein to provide for the development and confirmation of the methods used for: (1) establishing the irradiation exposure conditions within the RPV in the Embrittlement Data Base and Dosimetry Evaluation Program, (2) assessing the effects of irradiation on the RPV materials in the Heavy-Section Steel Irradiation Program, and (3) developing overall structural and fracture analyses of RPVs in the Heavy-Section Steel Technology Program

  17. A Dataset of Deep-Sea Fishes Surveyed by Research Vessels in the Waters around Taiwan

    Directory of Open Access Journals (Sweden)

    Kwang-Tsao Shao

    2014-12-01

    Full Text Available The study of deep-sea fish fauna is hampered by a lack of data due to the difficulty and high cost incurred in its surveys and collections. Taiwan is situated along the edge of the Eurasia fig, at the junction of three Large Marine Ecosystems or Ecoregions of the East China Sea, South China Sea and the Philippines. As nearly two-thirds of its surrounding marine ecosystems are deep-sea environments, Taiwan is expected to hold a rich diversity of deep-sea fish. However, in the past, no research vessels were employed to collect fish data on site. Only specimens, caught by bottom trawl fishing in the waters hundreds of meters deep and missing precise locality information, were collected from Dasi and Donggang fishing harbors. Began in 2001, with the support of National Science Council, research vessels were made available to take on the task of systematically collecting deep-sea fish specimens and occurrence records in the waters surrounding Taiwan. By the end of 2006, a total of 3,653 specimens, belonging to 26 orders, 88 families, 198 genera and 366 species, were collected in addition to data such as sampling site geographical coordinates and water depth, and fish body length and weight. The information, all accessible from the “Database of Taiwan’s Deep-Sea Fauna and Its Distribution (http://deepsea.biodiv.tw/” as part of the “Fish Database of Taiwan,” can benefit the study of temporal and spatial changes in distribution and abundance of fish fauna in the context of global deep-sea biodiversity.

  18. A miniature research vessel: A small-scale ocean-exploration demonstration of geophysical methods

    Science.gov (United States)

    Howell, S. M.; Boston, B.; Sleeper, J. D.; Cameron, M. E.; Togia, H.; Anderson, A.; Sigurdardottir, T. D.; Tree, J. P.

    2015-12-01

    Graduate student members of the University of Hawaii Geophysical Society have designed a small-scale model research vessel (R/V) that uses sonar to create 3D maps of a model seafloor in real-time. A pilot project was presented to the public at the School of Ocean and Earth Science and Technology's (SOEST) Biennial Open House weekend in 2013 and, with financial support from the Society of Exploration Geophysicists and National Science Foundation, was developed into a full exhibit for the same event in 2015. Nearly 8,000 people attended the two-day event, including children and teachers from Hawaii's schools, home school students, community groups, families, and science enthusiasts. Our exhibit demonstrates real-time sonar mapping of a cardboard volcano using a toy size research vessel on a programmable 2-dimensional model ship track suspended above a model seafloor. Ship waypoints were wirelessly sent from a Windows Surface tablet to a large-touchscreen PC that controlled the exhibit. Sound wave travel times were recorded using an ultrasonic emitter/receiver attached to an Arduino microcontroller platform and streamed through a USB connection to the control PC running MatLab, where a 3D model was updated as the ship collected data. Our exhibit demonstrates the practical use of complicated concepts, like wave physics, survey design, and data processing in a way that the youngest elementary students are able to understand. It provides an accessible avenue to learn about sonar mapping, and could easily be adapted to talk about bat and marine mammal echolocation by replacing the model ship and volcano. The exhibit received an overwhelmingly positive response from attendees and incited discussions that covered a broad range of earth science topics.

  19. MOSES, development of an Underwater Warfare Testbed

    NARCIS (Netherlands)

    Lentze, S.G.

    2001-01-01

    The TNO underwater warfare (UWW) research programme results in a large number of models used in operational research projects. To enhance the accessibility and re-use of these models for new projects, TNO-FEL has developed the modelling environment ‘MOSES - Maritime Operations Simulation and

  20. Underwater cutting techniques developments

    International Nuclear Information System (INIS)

    Bach, F.-W.

    1990-01-01

    The primary circuit structures of different nuclear powerplants are constructed out of stainless steels, ferritic steels, plated ferritic steels and alloys of aluminium. According to the level of the specific radiation of these structures, it is necessary for dismantling to work with remote controlled cutting techniques. The most successful way to protect the working crew against exposure of radiation is to operate underwater in different depths. The following thermal cutting processes are more or less developed to work under water: For ferritic steels only - flame cutting; For ferritic steels, stainless steels, cladded steels and aluminium alloys - oxy-arc-cutting, arc-waterjet-cutting with a consumable electrode, arc-saw-cutting, plasma-arc-cutting and plasma-arc-saw. The flame cutting is a burning process, all the other processes are melt-cutting processes. This paper explains the different techniques, giving a short introduction of the theory, a discussion of the possibilities with the advantages and disadvantages of these processes giving a view into the further research work in this interesting field. (author)

  1. Underwater 3D filming

    OpenAIRE

    Rinaldi, Roberto

    2014-01-01

    After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie’s box offices due to the overall quality of its products. Special environments such as space (“Gravity” ) and the underwater realm look perfect to be reproduced in 3D. “Filming in space” was possible in “Gravity” using special effects and computer graphic. The underwater realm is still difficult to be handled. Unde...

  2. Impacts of underwater noise on marine vertebrates

    NARCIS (Netherlands)

    Liebschner, Alexander; Seibel, Henrike; Teilmann, Jonas; Wittekind, Dietrich; Parmentier, Eric; Dähne, Michael; Dietz, Rune; Driver, Jörg; Elk, van Cornelis; Everaarts, Eligius; Findeisen, Henning; Kristensen, Jacob; Lehnert, Kristina; Lucke, Klaus; Merck, Thomas; Müller, Sabine; Pawliczka, Iwona; Ronnenberg, Katrin; Rosenberger, Tanja; Ruser, Andreas; Tougaard, Jakob; Schuster, Max; Sundermeyer, Janne; Sveegaard, Signe; Siebert, Ursula

    2016-01-01

    The project conducts application-oriented research on impacts of underwater noise on marine vertebrates in the North and Baltic Seas. In distinct subprojects, the hearing sensitivity of harbor porpoises and gray seals as well as the acoustic tolerance limit of harbor porpoises to impulsive noise

  3. Crafting glass vessels: current research on the ancient glass collections in the Freer Gallery of Art, Washington, D.C.

    Science.gov (United States)

    Nagel, Alexander; McCarthy, Blythe; Bowe, Stacy

    Our knowledge of glass production in ancient Egypt has been well augmented by the publication of recently excavated materials and glass workshops, but also by more recent materials analysis, and experiments of modern glass-makers attempting to reconstruct the production process of thin-walled coreformed glass vessels. From the mounting of a prefabricated core to the final glass product our understanding of this profession has much improved. The small but well preserved glass collection of the Freer Gallery of Art in Washington, D.C. is a valid tool for examining and studying the technology and production of ancient Egyptian core formed glass vessels. Charles Lang Freer (1854-1919) acquired most of the material from Giovanni Dattari in Cairo in 1909. Previously the glass had received only limited discussion, suggesting that most of these vessels were produced in the 18th Dynasty in the 15th and 14th centuries BCE, while others date from the Hellenistic period and later. In an ongoing project we conducted computed radiography in conjunction with qualitative x-ray fluorescence analysis on a selected group of vessels to understand further aspects of the ancient production process. This paper will provide an overview of our recent research and present our data-gathering process and preliminary results. How can the examinations of core formed glass vessels in the Freer Gallery contribute to our understanding of ancient glass production and technology? By focusing on new ways of looking at old assumptions using the Freer Gallery glass collections, we hope to increase understanding of the challenges of the production process of core-vessel technology as represented by these vessels.

  4. QFD-ANP Approach for the Conceptual Design of Research Vessels: A Case Study

    Science.gov (United States)

    Venkata Subbaiah, Kambagowni; Yeshwanth Sai, Koneru; Suresh, Challa

    2016-10-01

    Conceptual design is a subset of concept art wherein a new idea of product is created instead of a visual representation which would directly be used in a final product. The purpose is to understand the needs of conceptual design which are being used in engineering designs and to clarify the current conceptual design practice. Quality function deployment (QFD) is a customer oriented design approach for developing new or improved products and services to enhance customer satisfaction. House of quality (HOQ) has been traditionally used as planning tool of QFD which translates customer requirements (CRs) into design requirements (DRs). Factor analysis is carried out in order to reduce the CR portions of HOQ. The analytical hierarchical process is employed to obtain the priority ratings of CR's which are used in constructing HOQ. This paper mainly discusses about the conceptual design of an oceanographic research vessel using analytical network process (ANP) technique. Finally the QFD-ANP integrated methodology helps to establish the importance ratings of DRs.

  5. Swarm Underwater Acoustic 3D Localization: Kalman vs Monte Carlo

    Directory of Open Access Journals (Sweden)

    Sergio Taraglio

    2015-07-01

    Full Text Available Two three-dimensional localization algorithms for a swarm of underwater vehicles are presented. The first is grounded on an extended Kalman filter (EKF scheme used to fuse some proprioceptive data such as the vessel's speed and some exteroceptive measurements such as the time of flight (TOF sonar distance of the companion vessels. The second is a Monte Carlo particle filter localization processing the same sensory data suite. The results of several simulations using the two approaches are presented, with comparison. The case of a supporting surface vessel is also considered. An analysis of the robustness of the two approaches against some system parameters is given.

  6. The influence of fire exposure on austenitic stainless steel for pressure vessel fitness-for-service assessment: Experimental research

    Science.gov (United States)

    Li, Bo; Shu, Wenhua; Zuo, Yantian

    2017-04-01

    The austenitic stainless steels are widely applied to pressure vessel manufacturing. The fire accident risk exists in almost all the industrial chemical plants. It is necessary to make safety evaluation on the chemical equipment including pressure vessels after fire. Therefore, the present research was conducted on the influences of fire exposure testing under different thermal conditions on the mechanical performance evolution of S30408 austenitic stainless steel for pressure vessel equipment. The metallurgical analysis described typical appearances in micro-structure observed in the material suffered by fire exposure. Moreover, the quantitative degradation of mechanical properties was investigated. The material thermal degradation mechanism and fitness-for-service assessment process of fire damage were further discussed.

  7. Overview of research trends and problems on Cr-Mo low alloy steels for pressure vessel

    International Nuclear Information System (INIS)

    Chi, Byung Ha; Kim, Jeong Tae

    2000-01-01

    Cr-Mo low alloy steels have been used for a long time for pressure vessel due to its excellent corrosion resistance, high temperature strength and toughness. The paper reviewed the latest trends on material development and some problems on Cr-Mo low alloy steel for pressure vessel, such as elevated temperature strength, hardenability, synergetic effect between temper and hydrogen embrittlement, hydrogen attack and hydrogen induced disbonding of overlay weld-cladding

  8. Vessel generator noise as a settlement cue for marine biofouling species.

    Science.gov (United States)

    McDonald, J I; Wilkens, S L; Stanley, J A; Jeffs, A G

    2014-01-01

    Underwater noise is increasing globally, largely due to increased vessel numbers and international ocean trade. Vessels are also a major vector for translocation of non-indigenous marine species which can have serious implications for biosecurity. The possibility that underwater noise from fishing vessels may promote settlement of biofouling on hulls was investigated for the ascidian Ciona intestinalis. Spatial differences in biofouling appear to be correlated with spatial differences in the intensity and frequency of the noise emitted by the vessel's generator. This correlation was confirmed in laboratory experiments where C. intestinalis larvae showed significantly faster settlement and metamorphosis when exposed to the underwater noise produced by the vessel generator. Larval survival rates were also significantly higher in treatments exposed to vessel generator noise. Enhanced settlement attributable to vessel generator noise may indicate that vessels not only provide a suitable fouling substratum, but vessels running generators may be attracting larvae and enhancing their survival and growth.

  9. Research and development of spent fuel shipping casks and the criteria for seagoing vessel carrying casks

    International Nuclear Information System (INIS)

    Aoki, S.; Ando, Y.

    1977-01-01

    Considering that the transportation of spent fuel will increase rapidly and extensively in the near future, Japanese Atomic Energy Committee enacted ''Technical Standard for Transportation of Radioactive Materials'' based on ''IAEA Regulation for the Safe Transport of Radioactive Materials 1973 Revised Edition''. Coping with the recommendation of AEC, Atomic Energy Bureau in Science and Technology Agency and other authorities concerned started to review the former ordinances for transportation of radioactive materials and to consolidate a unified system of relevant laws and standards. On the other hand, Atomic Energy Bureau has invested in research and development since ten years ago in order to obtain the data for design and licensing work of spent fuel shipping casks. In those studies some different scale models of a prototype of 80 t in weight have been used to make clear the scale effect at the drop, pucture and fire tests, which are one of the features of Japanese research and development. And also the immersion test in high pressure water up to about 500 bars is now carried out to investigate the integrity of cask body and sealing structure to prevent leakage of radioactive contents to the ambient when the cask falls into deep sea. In Japan, depending on the site conditions of nuclear plants, almost all transportations of unirradiated and spent fuels are done on the sea. Therefore, in order to secure the safety of transportation, the design criteria of the seagoing vessels for exclusive transportation of spent fuel shipping casks, namely full load shipping, has been enacted, which aims to make minimum the probability of sinking at collison, stranding and other unforeseen accidents at sea and also to restrain radiation exposure of the crew as low as possible

  10. Silent Localization of Underwater Sensors Using Magnetometers

    Directory of Open Access Journals (Sweden)

    Jonas Callmer

    2010-01-01

    Full Text Available Sensor localization is a central problem for sensor networks. If the sensor positions are uncertain, the target tracking ability of the sensor network is reduced. Sensor localization in underwater environments is traditionally addressed using acoustic range measurements involving known anchor or surface nodes. We explore the usage of triaxial magnetometers and a friendly vessel with known magnetic dipole to silently localize the sensors. The ferromagnetic field created by the dipole is measured by the magnetometers and is used to localize the sensors. The trajectory of the vessel and the sensor positions are estimated simultaneously using an Extended Kalman Filter (EKF. Simulations show that the sensors can be accurately positioned using magnetometers.

  11. Summary Report Panel 1: The Need for Protocols and Standards in Research on Underwater Noise Impacts on Marine Life.

    Science.gov (United States)

    Erbe, Christine; Ainslie, Michael A; de Jong, Christ A F; Racca, Roberto; Stocker, Michael

    2016-01-01

    As concern about anthropogenic noise and its impacts on marine fauna is increasing around the globe, data are being compared across populations, species, noise sources, geographic regions, and time. However, much of the raw and processed data are not comparable due to differences in measurement methodology, analysis and reporting, and a lack of metadata. Common protocols and more formal, international standards are needed to ensure the effectiveness of research, conservation, regulation and practice, and unambiguous communication of information and ideas. Developing standards takes time and effort, is largely driven by a few expert volunteers, and would benefit from stakeholders' contribution and support.

  12. Reactor pressure vessel structural integrity research in the US Nuclear Regulatory Commission HSST and HSSI Programs

    International Nuclear Information System (INIS)

    Pennell, W.E.; Corwin, W.R.

    1994-01-01

    This report discusses development on the technology used to assess the safety of irradiation-embrittled nuclear reactor pressure vessels containing flaws. Fracture mechanics tests on reactor pressure vessel steel have shown that local brittle zones do not significantly degrade the material fracture toughness, constraint relaxation at the crack tip of shallow surface flaws results in increased fracture toughness, and biaxial loading reduces but does not eliminate the shallow-flaw fracture toughness elevation. Experimental irradiation investigations have shown that the irradiation-induced shift in Charpy V-notch versus temperature behavior may not be adequate to conservatively assess fracture toughness shifts due to embrittlement and the wide global variations of initial chemistry and fracture properties of a nominally uniform material within a pressure vessel may confound accurate integrity assessments that require baseline properties

  13. Colour reconstruction of underwater images

    OpenAIRE

    Hoth, Julian; Kowalczyk, Wojciech

    2017-01-01

    Objects look very different in the underwater environment compared to their appearance in sunlight. Images with correct colouring simplify the detection of underwater objects and may allow the use of visual SLAM algorithms developed for land-based robots underwater. Hence, image processing is required. Current algorithms focus on the colour reconstruction of scenery at diving depth where different colours can still be distinguished. At greater depth this is not the case. In this study it is i...

  14. Underwater Welding Techniques

    OpenAIRE

    Esam F. Alajmi; Ahmad A. Alqenaei

    2017-01-01

    Welding demand in offshore and marine applications is increased with the increasing in oil and gas activities as well as increasing in the marine transportation and industrial applications. Applications of underwater welding well be increased in Kuwait in the coming years due to the strategic directive of the country toward starting the offshore oil and gas exploration and production, and the increase in marine transportation projects. Therefore, there is a need to understand the concept of u...

  15. Vessel Operating Units (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains data for vessels that are greater than five net tons and have a current US Coast Guard documentation number. Beginning in1979, the NMFS...

  16. Digital sonar design in underwater acoustics principles and applications

    CERN Document Server

    Li, Qihu

    2012-01-01

    "Digital Sonar Design in Underwater Acoustics Principles and Applications" provides comprehensive and up-to-date coverage of research on sonar design, including the basic theory and techniques of digital signal processing, basic concept of information theory, ocean acoustics, underwater acoustic signal propagation theory, and underwater signal processing theory. This book discusses the general design procedure and approaches to implementation, the design method, system simulation theory and techniques, sonar tests in the laboratory, lake and sea, and practical validation criteria and methods for digital sonar design. It is intended for researchers in the fields of underwater signal processing and sonar design, and also for navy officers and ocean explorers. Qihu Li is a professor at the Institute of Acoustics, Chinese Academy of Sciences, and an academician of the Chinese Academy of Sciences.

  17. Neuroimaging standards for research into small vessel disease and its contribution to ageing and neurodegeneration

    NARCIS (Netherlands)

    Wardlaw, J.M.; Smith, E.E.; Biessels, G.J.; Cordonnier, C.; Fazekas, F.; Frayne, R.; Lindley, R.I.; O'Brien, J. T.; Barkhof, F.; Benavente, O.R.; Black, S.E.; Brayne, C.; Breteler, M.; Chabriat, H.; deCarli, C.; de Leeuw, F.E.; Doubal, F.; Duering, M.; Fox, N.C.; Greenberg, S.; Hachinski, V.; Kilimann, I.; Mok, V.; van Oostenbrugge, R.; Pantoni, L.; Speck, O.; Stephan, B.C.M.; Teipel, S.; Viswanathan, A.; Werring, D.; Chen, C.; Smith, C.; van Buchem, M.; Norrving, B.; Gorelick, P.B.; Dichgans, M.

    2013-01-01

    Cerebral small vessel disease (SVD) is a common accompaniment of ageing. Features seen on neuroimaging include recent small subcortical infarcts, lacunes, white matter hyperintensities, perivascular spaces, microbleeds, and brain atrophy. SVD can present as a stroke or cognitive decline, or can have

  18. Mock-up test of remote controlled dismantling apparatus for large-sized vessels (contract research)

    Energy Technology Data Exchange (ETDEWEB)

    Myodo, Masato; Miyajima, Kazutoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Okane, Shogo [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

    2001-03-01

    The Remote dismantling apparatus, which is equipped with multi-units for functioning of washing, cutting, collection of cut pieces and so on, has been constructed to dismantle the large-sized vessels in the JAERI's Reprocessing Test Facility (JRTF). The apparatus has five-axis movement capability and its operation is performed remotely. The mock-up tests were performed to evaluate the applicability of the apparatus to actual dismantling activities by using the mock-ups of LV-3 and LV-5 in the facility. It was confirmed that each unit was satisfactory functioned by remote operation. Efficient procedures for dismantling the large-sized vessel was studied and various date was obtained in the mock-up tests. This apparatus was found to be applicable for the actual dismantling activity in JRTF. (author)

  19. A group of painted vessels from Singidunum: A contribution to the researches on painted ceramics

    Directory of Open Access Journals (Sweden)

    Nikolić Snežana

    2005-01-01

    Full Text Available About 20 vessels, made of fine clay fired in whitish tones (10YR 8/2, 10YR 8/2-3, 5Y 8/1, with the polished surface ornamented with painting in fading brown, originate from Singidunum. In comparison with analogous material from Donja (Lower Panonia and Dalmatia, the importance of these vessels is to be found in the fact that they were excavated from settlement horizons dated to the second half of the 3rd and early 4th century. Based on the shapes and technological features of ceramics from Lower Panonia and Dalmatia, which have been published, as well as on the observations of the finds from Singidunum, it is to be assumed that they were the output of the same workshop which not only had a small scale of production but also a meager scope of shapes, meaning goblets i.e. cups as favorable form.

  20. Mock-up test of remote controlled dismantling apparatus for large-sized vessels (contract research)

    International Nuclear Information System (INIS)

    Myodo, Masato; Miyajima, Kazutoshi; Okane, Shogo

    2001-03-01

    The Remote dismantling apparatus, which is equipped with multi-units for functioning of washing, cutting, collection of cut pieces and so on, has been constructed to dismantle the large-sized vessels in the JAERI's Reprocessing Test Facility (JRTF). The apparatus has five-axis movement capability and its operation is performed remotely. The mock-up tests were performed to evaluate the applicability of the apparatus to actual dismantling activities by using the mock-ups of LV-3 and LV-5 in the facility. It was confirmed that each unit was satisfactory functioned by remote operation. Efficient procedures for dismantling the large-sized vessel was studied and various date was obtained in the mock-up tests. This apparatus was found to be applicable for the actual dismantling activity in JRTF. (author)

  1. Study of archaeological underwater finds: deterioration and conservation

    Science.gov (United States)

    Crisci, G. M.; La Russa, M. F.; Macchione, M.; Malagodi, M.; Palermo, A. M.; Ruffolo, S. A.

    2010-09-01

    This study is aimed at an assessment of the methodologies, instruments and new applications for underwater archaeology. Research focused on study of the various kinds of degradation affecting underwater finds and stone materials aged in underwater environment, efficiency evaluation of various surface cleaning methods and study and mixing of protective products with consolidating resins and antimicrobial biocides to be applied to restored underwater finds. Transmitted light optical microscopy and scanning electron microscopy (SEM) were used to study surface biofilms and the interactions with samples of different stone materials such as brick, marble and granite immersed in the submarine archaeological area of Crotone (South of Italy). Surface cleaning tests were performed with application of ion exchange resins, EDTA, hydrogen peroxide and ultrasound techniques. Capillary water absorption, simulated solar ageing and colourimetric measurements were carried out to evaluate hydrophobic and consolidant properties; to assess biocidal efficacy, heterotrophic micro-organisms ( Aspergillus niger) were inoculated on agar plates and growth inhibition was measured.

  2. Wireless Underwater Monitoring Systems Based on Energy Harvestings

    Directory of Open Access Journals (Sweden)

    Sea-Hee HWANGBO

    2013-01-01

    Full Text Available One of the important research fields for aquatic exploitation and conservation is underwater wireless sensor network. Since limited energy source for underwater nodes and devices is a main open problem, in this paper, we propose wireless underwater monitoring systems powered by energy harvester which resolves the energy constraint. The target system generates renewable energy from energy harvester and shares the energy with underwater sensor nodes. For the realization of the system, key components to be investigated are discriminated as follows: acoustic modem, actuator, smart battery charge controller, energy harvester and wireless power transfer module. By developing acoustic modem, actuator and smart battery charge controller and utilizing off-the-shelf energy harvester and wireless power transfer module, we design and implement a prototype of the system. Also, we verify the feasibility of concept of target system by conducting indoor and outdoor experiments.

  3. Filming Underwater in 3d Respecting Stereographic Rules

    Science.gov (United States)

    Rinaldi, R.; Hordosch, H.

    2015-04-01

    After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie's box offices due to the overall quality of its products. Special environments such as space ("Gravity") and the underwater realm look perfect to be reproduced in 3D. "Filming in space" was possible in "Gravity" using special effects and computer graphic. The underwater realm is still difficult to be handled. Underwater filming in 3D was not that easy and effective as filming in 2D, since not long ago. After almost 3 years of research, a French, Austrian and Italian team realized a perfect tool to film underwater, in 3D, without any constrains. This allows filmmakers to bring the audience deep inside an environment where they most probably will never have the chance to be.

  4. FILMING UNDERWATER IN 3D RESPECTING STEREOGRAPHIC RULES

    Directory of Open Access Journals (Sweden)

    R. Rinaldi

    2015-04-01

    Full Text Available After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie’s box offices due to the overall quality of its products. Special environments such as space ("Gravity" and the underwater realm look perfect to be reproduced in 3D. "Filming in space" was possible in "Gravity" using special effects and computer graphic. The underwater realm is still difficult to be handled. Underwater filming in 3D was not that easy and effective as filming in 2D, since not long ago. After almost 3 years of research, a French, Austrian and Italian team realized a perfect tool to film underwater, in 3D, without any constrains. This allows filmmakers to bring the audience deep inside an environment where they most probably will never have the chance to be.

  5. Euclidean reconstruction of natural underwater scenes using optic imagery sequence

    Science.gov (United States)

    Hu, Han

    The development of maritime applications require monitoring, studying and preserving of detailed and close observation on the underwater seafloor and objects. Stereo vision offers advanced technologies to build 3D models from 2D still overlapping optic images in a relatively inexpensive way. However, while image stereo matching is a necessary step in 3D reconstruction procedure, even the most robust dense matching techniques are not guaranteed to work for underwater images due to the challenging aquatic environment. In this thesis, in addition to a detailed introduction and research on the key components of building 3D models from optic images, a robust modified quasi-dense matching algorithm based on correspondence propagation and adaptive least square matching for underwater images is proposed and applied to some typical underwater image datasets. The experiments demonstrate the robustness and good performance of the proposed matching approach.

  6. Advance of investigation of irradiation embrittlement mechanism of nuclear reactor pressure vessel steels. History and future of irradiation embrittlement researches

    International Nuclear Information System (INIS)

    Ishino, Shiori

    2007-01-01

    The nuclear reactor pressure vessel is the most important component of LWR plants required to be safe. This paper describes contents of the title consisting of four chapters. The first chapter states the general theory of irradiation effects, irradiation embrittlement and decreasing of toughness, and some kinds of pressure vessel steels. The second chapter explains history of irradiation embrittlement investigations and the advance of research methods for experiments and calculation. The third chapter contains information of inner structure of irradiated materials and development of prediction equations, recent information of embrittlement mechanism and mechanism guided prediction method, USA model and Central Research Institute of Electric Power Industry (CRIEPI) model. The fourth chapter states recent problems from viewpoints of experimental and analytical approaches. Comparison of standards of LWR pressure vessel steels between Japan and USA, relation between the density of number of cluster and the copper content, effect of flux on clustering of copper atoms, and CRIEPI's way of approaching the prediction method are illustrated. (S.Y.)

  7. Estimation on the Flow Phenomena and the Pressure Loss for the Inlet Part of a Research Reactor Vessel

    International Nuclear Information System (INIS)

    Seo, Kyoung Woo; Oh, Jae Min; Seo, Jae Kwang; Yoon, Ju Hyeon; Lee, Doo Jeong

    2009-01-01

    For a research reactor, a conceptual primary cooling system (PCS) was designed for an adequate cooling to the reactor core. The developed primary cooling circuit consisted of decay tanks, pumps, heat exchangers, vacuum breakers, some isolation and check valves, connection piping, and instruments. The main function of the primary cooling pumps (PCPs) of the PCS was to circulate the reactor coolant through the fuel core and the heat exchangers during a normal operation. The head according to the design flow rate which was determined by the thermal hydraulic design analysis for the core should be estimated to design the PCPs in the fluid system. The pressure loss in the PCS can be calculated by the dimensional analysis of the pipe flow and the head loss coefficient of the components. However, it is insufficient to estimate the pressure loss for 3-dimensional flow phenomena such as the flow path in the reactor with the theoretical dimensional analysis based on experimental data. The purpose of this research is to evaluate the pressure loss of the part of a research reactor vessel. For evaluating the pressure loss, the commercially available CFD computer model, FLUENT, was employed. First, for validating the application of FLUENT to the pressure loss, a simple case was calculated and compared with the Idelchik empirical correlation. Secondly, several cases for the inlet part of a research reactor vessel were estimated by a FLUENT 3- dimensional calculation

  8. Deep Learning Methods for Underwater Target Feature Extraction and Recognition

    Directory of Open Access Journals (Sweden)

    Gang Hu

    2018-01-01

    Full Text Available The classification and recognition technology of underwater acoustic signal were always an important research content in the field of underwater acoustic signal processing. Currently, wavelet transform, Hilbert-Huang transform, and Mel frequency cepstral coefficients are used as a method of underwater acoustic signal feature extraction. In this paper, a method for feature extraction and identification of underwater noise data based on CNN and ELM is proposed. An automatic feature extraction method of underwater acoustic signals is proposed using depth convolution network. An underwater target recognition classifier is based on extreme learning machine. Although convolution neural networks can execute both feature extraction and classification, their function mainly relies on a full connection layer, which is trained by gradient descent-based; the generalization ability is limited and suboptimal, so an extreme learning machine (ELM was used in classification stage. Firstly, CNN learns deep and robust features, followed by the removing of the fully connected layers. Then ELM fed with the CNN features is used as the classifier to conduct an excellent classification. Experiments on the actual data set of civil ships obtained 93.04% recognition rate; compared to the traditional Mel frequency cepstral coefficients and Hilbert-Huang feature, recognition rate greatly improved.

  9. Optimal Node Placement in Underwater Acoustic Sensor Network

    KAUST Repository

    Felemban, Muhamad

    2011-10-01

    Almost 70% of planet Earth is covered by water. A large percentage of underwater environment is unexplored. In the past two decades, there has been an increase in the interest of exploring and monitoring underwater life among scientists and in industry. Underwater operations are extremely difficult due to the lack of cheap and efficient means. Recently, Wireless Sensor Networks have been introduced in underwater environment applications. However, underwater communication via acoustic waves is subject to several performance limitations, which makes the relevant research issues very different from those on land. In this thesis, we investigate node placement for building an initial Underwater Wireless Sensor Network infrastructure. Firstly, we formulated the problem into a nonlinear mathematic program with objectives of minimizing the total transmission loss under a given number of sensor nodes and targeted volume. We conducted experiments to verify the proposed formulation, which is solved using Matlab optimization tool. We represented each node with a truncated octahedron to fill out the 3D space. The truncated octahedrons are tiled in the 3D space with each node in the center where locations of the nodes are given using 3D coordinates. Results are supported using ns-3 simulator. Results from simulation are consistent with the obtained results from mathematical model with less than 10% error.

  10. Reactor vessel dismantling at the high flux materials testing reactor Petten

    International Nuclear Information System (INIS)

    Tas, A.; Teunissen, G.

    1986-01-01

    The project of replacing the reactor vessel of the high flux materials testing reactor (HFR) originated in 1974 when results of several research programs confirmed severe neutron embrittlement of aluminium alloys suggesting a limited life of the existing facility. This report describes the dismantling philosophy and organisation, the design of special underwater equipment, the dismantling of the reactor vessel and thermal column, and the conditioning and shielding activities resulting in a working area for the installation of the new vessel with no access limitations due to radiation. Finally an overview of the segmentation, waste disposal and radiation exposure is given. The total dismantling, segmentation and conditioning activities resulted in a total collective radiation dose of 300 mSv. (orig.) [de

  11. Underwater noise modelling for environmental impact assessment

    Energy Technology Data Exchange (ETDEWEB)

    Farcas, Adrian [Centre for Environment, Fisheries and Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT (United Kingdom); Thompson, Paul M. [Lighthouse Field Station, Institute of Biological and Environmental Sciences, University of Aberdeen, Cromarty IV11 8YL (United Kingdom); Merchant, Nathan D., E-mail: nathan.merchant@cefas.co.uk [Centre for Environment, Fisheries and Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT (United Kingdom)

    2016-02-15

    Assessment of underwater noise is increasingly required by regulators of development projects in marine and freshwater habitats, and noise pollution can be a constraining factor in the consenting process. Noise levels arising from the proposed activity are modelled and the potential impact on species of interest within the affected area is then evaluated. Although there is considerable uncertainty in the relationship between noise levels and impacts on aquatic species, the science underlying noise modelling is well understood. Nevertheless, many environmental impact assessments (EIAs) do not reflect best practice, and stakeholders and decision makers in the EIA process are often unfamiliar with the concepts and terminology that are integral to interpreting noise exposure predictions. In this paper, we review the process of underwater noise modelling and explore the factors affecting predictions of noise exposure. Finally, we illustrate the consequences of errors and uncertainties in noise modelling, and discuss future research needs to reduce uncertainty in noise assessments.

  12. Underwater noise modelling for environmental impact assessment

    International Nuclear Information System (INIS)

    Farcas, Adrian; Thompson, Paul M.; Merchant, Nathan D.

    2016-01-01

    Assessment of underwater noise is increasingly required by regulators of development projects in marine and freshwater habitats, and noise pollution can be a constraining factor in the consenting process. Noise levels arising from the proposed activity are modelled and the potential impact on species of interest within the affected area is then evaluated. Although there is considerable uncertainty in the relationship between noise levels and impacts on aquatic species, the science underlying noise modelling is well understood. Nevertheless, many environmental impact assessments (EIAs) do not reflect best practice, and stakeholders and decision makers in the EIA process are often unfamiliar with the concepts and terminology that are integral to interpreting noise exposure predictions. In this paper, we review the process of underwater noise modelling and explore the factors affecting predictions of noise exposure. Finally, we illustrate the consequences of errors and uncertainties in noise modelling, and discuss future research needs to reduce uncertainty in noise assessments.

  13. CTD and Water Sample Data from Research Vessel Robert Gordon Sproul in the NE Pacific, 24 October 2013 (NCEI Accession 0157082)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The expedition by research vessel Robert Gordon Sproul from 23 to 25 October 2013 had the objective to recover a broken mooring from the CORC project (Consortium on...

  14. CTD and Water Sample Data from Research Vessel New Horizon in the NE Pacific, 19-22 September 2008 (NCEI Accession 0156931)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The expedition by research vessel New Horizon from 19 to 22 September 2008 had the objective to deploy a number of moored platforms for the CORC project (Consortium...

  15. Processed CTD and Water Sample Data from Research Vessel Ocean Starr in the NE Pacific, Aug. 31 and Sept. 01, 2012 (NCEI Accession 0156932)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The expedition by research vessel Ocean Starr on Aug. 31 and Sept. 01, 2012 had the objective to recover and re-deploy a number of moored platforms from the CORC...

  16. Processed CTD and Water Sample Data from Research Vessel Roger Revelle, Expedition RR1214, in the NE Pacific in November 2012 (NCEI Accession 0156228)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Expedition RR1214 by research vessel Roger Revelle was primarily a transit from French Polynesia to the US mainland. However, a small scientific program was...

  17. OFDM for underwater acoustic communications

    CERN Document Server

    Zhou, Shengli

    2014-01-01

    A blend of introductory material and advanced signal processing and communication techniques, of critical importance to underwater system and network development This book, which is the first to describe the processing techniques central to underwater OFDM, is arranged into four distinct sections: First, it describes the characteristics of underwater acoustic channels, and stresses the difference from wireless radio channels. Then it goes over the basics of OFDM and channel coding. The second part starts with an overview of the OFDM receiver, and develops various modules for the receiver des

  18. Research and development on in-service inspection system for reactor vessel of FBR's

    International Nuclear Information System (INIS)

    Rindo, Hiroshi; Mitabe, Noriaki; Ara, Kuniaki; Nagai, Keiichi; Otaka, Masahiko

    1993-01-01

    In-Service Inspection (ISI) is required for main components and piping of FBRs. Visual test and volumetric examination of the reactor vessel (RV) from the outer surface are to be performed under severe conditions such as limited space, high temperature and high gamma dose rate during the reactor shutdown. Therefore, ISI should be performed by using a remote operation system, and the ISI system should be very compact. PNC has been developing the ISI system to apply to the RV inspection. Verification and performance tests of ISI system were carried out by use of the RV test model. This paper describes the system structure, system verification tests including operation and controlling the inspection robot, the functions of the visual test and the volumetric examination under the high temperature

  19. Development of in-vessel type control rod drive mechanism for a innovative small reactor (Contract research)

    Energy Technology Data Exchange (ETDEWEB)

    Yoritsune, Tsutomu; Ishida, Toshihisa [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    Although the control rod drive mechanism of an existing large scale light water reactor is generally installed outside the reactor vessel, an in-vessel type control rod drive mechanism (INV-CRDM) is installed inside the reactor vessel. The INV-CRDM contributes to compactness and simplicity of the reactor system, and it can eliminate the possibility of a rod ejection accident. Therefore, INV-CRDM is an important technology adopted in an innovative small reactor. Japan Atomic Energy Research Institute (JAERI) has developed this type of CRDM driven by an electric motor, which can work under high temperature and high pressure water for the advanced marine reactor. On the basis of this research result, a driving motor coil and a bearing were developed to be used under the high temperature steam, severe condition for an innovative small reactor. About the driving motor, we manufactured the driving motor available for high temperature steam and carried out performance test under room temperature atmosphere to confirm the electric characteristic and coolability of the driving coil. With these test results and the past test results under high temperature water, we analyzed and evaluated the electric performance and coolability of the driving coil under high temperature steam. Concerning bearing, we manufactured the test pieces using some candidate material for material characteristic test and carried out the rolling wear test under high temperature steam to select the material. Consequently, we confirmed that performance of the driving coil for the advanced type driving motor, is enough to be used under high temperature steam. And, we evaluated the performance of the bearing and selected the material of the bearing, which can be used under high temperature steam. From these results, we have obtained the prospect that the INV-CRDM can be used for an innovative small reactor under steam atmosphere could be developed. (author)

  20. Applicability evaluation of eddy current testing for underwater laser beam welding

    International Nuclear Information System (INIS)

    Kobayashi, Noriyasu; Kasuya, Takashi; Ueno, Souichi; Ochiai, Makoto; Yuguchi, Yasuhiro

    2010-01-01

    We clarified a defect detecting capability of eddy current testing (ECT) as a surface inspection technique for underwater laser beam welding. An underwater laser beam welding procedure includes groove caving as a preparation, laser beam welding in groove and welding surface grinding as a post treatment. Therefore groove and grinded welding surface inspections are required underwater. We curried out defect detection tests using three kinds of specimens simulated a groove, reactor vessel nozzle dissimilar metal welding materials and a laser beam welding material with a cross coil ECT probe. From experimental results, we confirmed that it is possible to detect 0.3 mm or more depth electro-discharge machining slits on machining surfaces in all specimens and an ECT has possibility as a surface inspection technique for underwater laser beam welding. (author)

  1. Underwater plasma arc cutting

    International Nuclear Information System (INIS)

    Leautier, R.; Pilot, G.

    1991-01-01

    This report describes the work done to develop underwater plasma arc cutting techniques, to characterise aerosols from cutting operations on radioactive and non-radioactive work-pieces, and to develop suitable ventilation and filtration techniques. The work has been carried out in the framework of a contract between CEA-CEN Cadarache and the Commission of European Communities. Furthermore, this work has been carried out in close cooperation with CEA-CEN Saclay mainly for secondary emissions and radioactive analysis. The contract started in May 1986 and was completed in December 1988 by a supplementary agreement. This report has been compiled from several progress reports submitted during the work period, contains the main findings of the work and encloses the results of comparative tests on plasma arc cutting

  2. A Review of the Emerging Field of Underwater Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Emily Chua

    2016-11-01

    Full Text Available Mass spectrometers are versatile sensor systems, owing to their high sensitivity and ability to simultaneously measure multiple chemical species. Over the last two decades, traditional laboratory-based membrane inlet mass spectrometers have been adapted for underwater use. Underwater mass spectrometry has drastically improved our capability to monitor a broad suite of gaseous compounds (e.g., dissolved atmospheric gases, light hydrocarbons, and volatile organic compounds in the aquatic environment. Here we provide an overview of the progress made in the field of underwater mass spectrometry since its inception in the 1990s to the present. In particular, we discuss the approaches undertaken by various research groups in developing in situ mass spectrometers. We also provide examples to illustrate how underwater mass spectrometers have been used in the field. Finally, we present future trends in the field of in situ mass spectrometry. Most of these efforts are aimed at improving the quality and spatial and temporal scales of chemical measurements in the ocean. By providing up-to-date information on underwater mass spectrometry, this review offers guidance for researchers interested in adapting this technology as well as goals for future progress in the field.

  3. 46 CFR 176.650 - Alternative Hull Examination Program options: Divers or underwater ROV.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Alternative Hull Examination Program options: Divers or...) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) INSPECTION AND CERTIFICATION Hull and Tailshaft Examinations § 176.650 Alternative Hull Examination Program options: Divers or underwater ROV. To complete the...

  4. First hvdc underwater transmission links mainland and Vancouver

    Energy Technology Data Exchange (ETDEWEB)

    1967-06-01

    Delicate and complex equipment for North America's first hvdc underwater transmission line is being installed. The power link will connect British Columbia Hydro and power authority's switchyards on the mainland near Ladner with the western terminus of the transmission scheme at Duncan on Vancouver Island, a distance of 42 miles. Nearly 19 miles of the transmission will be underwater, between Tsawwassen and Galiano Island, and between Parker and Saltspring Islands. The remaining distance will be spanned by a conventional aerial conductor. The submarine conductor cable will be approximately 3-1/2 inches in diameter and its copper core will be sheathed in lead and armored with a ring of steel wire. The cable, which is being manufactured in Calais, France, and coiled in a planned sequence aboard the cable laying vessel, Marcel Bayard, will be placed across the Gulf of Georgia in the spring of 1968.

  5. Research on removal technologies of fuel debris and in-vessel structures using laser light (1). Research plan and research activities on FY2012

    International Nuclear Information System (INIS)

    Muramatsu, Toshiharu; Yamada, Tomonori; Hanari, Toshihide; Takebe, Toshihiko; Matsunaga, Yukihiro

    2013-08-01

    In decommissioning works of the Fukushima Daiichi nuclear power plants, it is required that fuel debris solidifying mixed materials of fuels and in-vessel structures should be removed. The fuel debris is considered to have characteristics, such as indefinite shapes, porous bodies, multi-compositions, higher hardness, etc. from the knowledge in decommissioning process of the Three Mile Island nuclear power plant. Laser lights are characterized by higher power density, local processability, remote controllability, etc. and can be performed thermal cutting and crushing-up for various materials which does not depend on fracture toughness. This report describes a research program and research activities in FY2012 aiming at developing removal system of fuel debris by the use of laser lights. Main results obtained from research activities in FY2012 are as follows: (1) Improvements of experimental infrastructures. A beam switching unit for an existing fiber laser system, an x-y-z tri-axes robot system to investigate remote control performances, and a particle image velocimetry (PIV) system for quantitation of assist gas flow characteristics were introduced to the experimental laboratory of our Applied Laser Technology Institute in Tsuruga. (2) Laser cutting performances for thick metal plates. To quantify laser cutting performance for thick metal plates of in-vessel structures, after the evaluation of the relationship between the kerf depth and amount of laser irradiation energy to the metal test piece, we evaluated for heat transfer behavior due to temperature measurement of thick metal plate on the laser cutting process. It is suggested that the heat diffusion into the cutting object can affect the heat input efficiency of the laser irradiation energy to kerf front. On the viewpoint of suppressing this thermal diffusion, it was found that it is important in improving the laser cutting performance to increase the ejection of molten metal by the assist gas, and to optimize

  6. Underwater radiation measuring device

    International Nuclear Information System (INIS)

    Seki, Noriyuki; Suzuki, Yasuo

    1998-01-01

    The present invention provides a device for measuring, under water, radiation from spent fuels (long members to be detected) of nuclear power plants and reprocessing facilities. Namely, a detecting insertion tube (insertion tube) is disposed so as to be in parallel with axial direction of the long member to be detected stored underwater. A γ-ray detector is inserted to the inside of the insertion tube. A driving mechanism is disposed for moving the γ-ray detector in axial direction inside of the insertion tube. The driving mechanism preferably has a system that it moves the γ-ray detector by winding a detection signal cable around a driving drum. The driving mechanism is formed by inserting and securing a driving tube having screws formed on the side surface and inserting it into the insertion tube. It may have a system of moving the γ-ray detector together with the driving tube while engaging the teeth of a driving transfer mechanism with the screws of the driving tube. (I.S.)

  7. An underwater shear compactor

    International Nuclear Information System (INIS)

    Biver, E.; Sims, J.

    1997-01-01

    This paper, originally presented at the WM'96 Conference in Tucson Arizona, describes a concept of a specialised decommissioning tool designed to operate underwater and to reduce the volume of radioactive components by shearing and compacting. The shear compactor was originally conceived to manage the size reduction of a variety of decommissioned stainless steel tubes stored within a reactor fuel cooling pond and which were consuming a substantial volume of the pond. The main objective of this tool was to cut the long tubes into shorter lengths and to compact them into a flat rectangular form which could be stacked on the pond floor, thus saving valuable space. The development programme, undertaken on this project, investigated a wide range of factors which could contribute to an extended cutting blade performance, ie: materials of construction, cutting blade shape and cutting loads required, shock effects, etc. The second phase was to review other aspects of the design, such as radiological protection, cutting blade replacement, maintenance, pond installation and resultant wall loads, water hydraulics, collection of products of shearing/compacting operations, corrosion of the equipment, control system, operational safety and the ability of the equipment to operate in dry environments. The paper summarises the extended work programme involved with this shear compactor tool. (author)

  8. Development of underwater laser cutting technology

    International Nuclear Information System (INIS)

    Sato, Seiichi; Inaba, Takanori; Inose, Koutarou; Matsumoto, Naoyuki; Sakakibara, Yuji

    2015-01-01

    In is desirable to use remote underwater device for the decommissioning work of highly radioactive components such as the nuclear internals from a view point of reducing the ranitidine exposure to the worker. Underwater laser cutting technology has advantages. First advantage in underwater laser cutting technology is that low reaction force during cutting, namely, remote operability is superior. Second point is that underwater laser cutting generates a little amount of secondary waste, because cutting kerf size is very small. Third point is that underwater laser cutting has low risk of the process delay, because device trouble is hard to happen. While underwater laser cutting has many advantages, the careful consideration in the safe treatment of the offgas which underwater laser cutting generates is necessary. This paper describes outline of underwater laser cutting technology developed by IHI Corporation (IHI) and that this technology is effective in various dismantling works in water. (author)

  9. Response margins investigation of piping dynamic analyses using the independent support motion method and PVRC [Pressure Vessel Research Committee] damping

    International Nuclear Information System (INIS)

    Bezler, P.; Wang, Y.K.; Reich, M.

    1988-03-01

    An evaluation of Independent Support Motion (ISM) response spectrum methods of analysis coupled with the Pressure Vessel Research Committee (PVRC) recommendation for damping, to compute the dynamic component of the seismic response of piping systems, was completed. Response estimates for five piping/structural systems were developed using fourteen variants of the ISM response spectrum method, the Uniform Support Motions response spectrum method and the ISM time history analysis method, all based on the PVRC recommendations for damping. The ISM/PVRC calculational procedures were found to exhibit orderly characteristics with levels of conservatism comparable to those obtained with the ISM/uniform damping procedures. Using the ISM/PVRC response spectrum method with absolute combination between group contributions provided consistently conservative results while using the ISM/PVRC response spectrum method with square root sum of squares combination between group contributions provided estimates of response which were deemed to be acceptable

  10. Pressure vessel design manual

    CERN Document Server

    Moss, Dennis R

    2013-01-01

    Pressure vessels are closed containers designed to hold gases or liquids at a pressure substantially different from the ambient pressure. They have a variety of applications in industry, including in oil refineries, nuclear reactors, vehicle airbrake reservoirs, and more. The pressure differential with such vessels is dangerous, and due to the risk of accident and fatality around their use, the design, manufacture, operation and inspection of pressure vessels is regulated by engineering authorities and guided by legal codes and standards. Pressure Vessel Design Manual is a solutions-focused guide to the many problems and technical challenges involved in the design of pressure vessels to match stringent standards and codes. It brings together otherwise scattered information and explanations into one easy-to-use resource to minimize research and take readers from problem to solution in the most direct manner possible. * Covers almost all problems that a working pressure vessel designer can expect to face, with ...

  11. Underwater Ship Husbandry Discharges

    Science.gov (United States)

    2011-11-01

    which entered into force in September of 2008, prohibits the use of harmful organotins such as tributyltin ( TBT ) in AFCs used on international...States. The use of TBT AFCs is explicitly prohibited under the VGP, and vessels must remove such coatings or paint over them to prevent toxic ...to hull husbandry include (1) the discharge of toxic chemicals used as biocides in AFCs and (2) biofouling as a vector for aquatic nuisance species

  12. US Navy Transfers Research Vessel to Philippine Navy > U.S. Pacific Command

    Science.gov (United States)

    , 2016 EMAIL PRINT Photos 1 of 1 SAN DIEGO (April 27, 2016) - Vice Adm. Nora Tyson, left, commander of Philippines oceanographic research and study capabilities. SAN DIEGO (April 27, 2016) - Vice Adm. Nora Tyson part in that relationship," said Vice Adm. Nora Tyson, commander, U.S. 3rd Fleet. "Today, we

  13. Historical summary of the heavy-section steel technology program and some related activities in light-water reactor pressure vessel safety research

    International Nuclear Information System (INIS)

    Whitman, G.D.

    1986-03-01

    The accomplishments of the Heavy-Section Steel Technology Program and other programs having a close relationship to the development of information used in the assessment of light-water reactor pressure vessel integrity are reviewed. The early Pressure Vessel Research Committee planning, the principals contributing to program formulation, the role of the US Atomic Energy Commission, and the developments under the US Nuclear Regulatory Commission sponsorship are identified. The need for major research and development accomplishments in fracture mechanics, heavy-section steel procurement, materials properties, irradiation effects, fatigue crack growth, and structural testing are summarized. The impact of program results on regulatory issues and the development of data used in the preparation of codes, standards, and guides are discussed. Continuing activities and recommendations for future research and development in support of pressure vessel integrity assessments are presented

  14. Underwater electric field detection system based on weakly electric fish

    Science.gov (United States)

    Xue, Wei; Wang, Tianyu; Wang, Qi

    2018-04-01

    Weakly electric fish sense their surroundings in complete darkness by their active electric field detection system. However, due to the insufficient detection capacity of the electric field, the detection distance is not enough, and the detection accuracy is not high. In this paper, a method of underwater detection based on rotating current field theory is proposed to improve the performance of underwater electric field detection system. First of all, we built underwater detection system based on the theory of the spin current field mathematical model with the help of the results of previous researchers. Then we completed the principle prototype and finished the metal objects in the water environment detection experiments, laid the foundation for the further experiments.

  15. Defect detectability of eddy current testing for underwater laser beam welding

    International Nuclear Information System (INIS)

    Ueno, Souichi; Kobayashi, Noriyasu; Ochiai, Makoto; Kasuya, Takashi; Yuguchi, Yasuhiro

    2011-01-01

    We clarified defect detectability of eddy current testing (ECT) as a surface inspection technique for underwater laser beam welding works of dissimilar metal welding (DMW) of reactor vessel nozzle. The underwater laser beam welding procedure includes groove caving as a preparation, laser beam welding in the grooves and welded surface grinding as a post treatment. Therefore groove and welded surface inspections are required in the underwater condition. The ECT is a major candidate as this inspection technique because a penetrant testing is difficult to perform in the underwater condition. Several kinds of experiments were curried out using a cross coil an ECT probe and ECT data acquisition system in order to demonstrate the ECT defect detectability. We used specimens, simulating groove and DMW materials at an RV nozzle, with electro-discharge machining (EDM) slits over it. Additionally, we performed a detection test for artificial stress corrosion cracking (SCC) defects. From these experimental results, we confirmed that an ECT was possible to detect EDM slits 0.3 mm or more in depth and artificial SCC defects 0.02 mm to 0.48 mm in depth on machined surface. Furthermore, the underwater ECT defect detectability is equivalent to that in air. We clarified an ECT is sufficiently usable as a surface inspection technique for underwater laser beam welding works. (author)

  16. UNDERWATER COATINGS FOR CONTAMINATION CONTROL

    International Nuclear Information System (INIS)

    Julia L. Tripp; Kip Archibald; Ann Marie Phillips; Joseph Campbell

    2004-01-01

    The Idaho National Laboratory (INL) deactivated several aging nuclear fuel storage basins. Planners for this effort were greatly concerned that radioactive contamination present on the basin walls could become airborne as the sides of the basins became exposed during deactivation and allowed to dry after water removal. One way to control this airborne contamination was to fix the contamination in place while the pool walls were still submerged. There are many underwater coatings available on the market for marine, naval and other applications. A series of tests were run to determine whether the candidate underwater fixatives were easily applied and adhered well to the substrates (pool wall materials) found in INL fuel pools. Lab-scale experiments were conducted by applying fourteen different commercial underwater coatings to four substrate materials representative of the storage basin construction materials, and evaluating their performance. The coupons included bare concrete, epoxy painted concrete, epoxy painted carbon steel, and stainless steel. The evaluation criteria included ease of application, adherence to the four surfaces of interest, no change on water clarity or chemistry, non-hazardous in final applied form and be proven in underwater applications. A proprietary two-part, underwater epoxy owned by S. G. Pinney and Associates was selected from the underwater coatings tested for application to all four pools. Divers scrubbed loose contamination off the basin walls and floors using a ship hull scrubber and vacuumed up the sludge. The divers then applied the coating using a special powered roller with two separate heated hoses that allowed the epoxy to mix at the roller surface was used to eliminate pot time concerns. The walls were successfully coated and water was removed from the pools with no detectable airborne contamination releases

  17. Roadmap for Nondestructive Evaluation of Reactor Pressure Vessel Research and Development by the Light Water Reactor Sustainability Program

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Cyrus M [ORNL; Nanstad, Randy K [ORNL; Clayton, Dwight A [ORNL; Matlack, Katie [Georgia Institute of Technology; Ramuhalli, Pradeep [Pacific Northwest National Laboratory (PNNL); Light, Glenn [Southwest Research Institute, San Antonio

    2012-09-01

    The Department of Energy s (DOE) Light Water Reactor Sustainability (LWRS) Program is a five year effort which works to develop the fundamental scientific basis to understand, predict, and measure changes in materials and systems, structure, and components as they age in environments associated with continued long-term operations of existing commercial nuclear power reactors. This year, the Materials Aging and Degradation (MAaD) Pathway of this program has placed emphasis on emerging Non-Destructive Evaluation (NDE) methods which support these objectives. DOE funded Research and Development (R&D) on emerging NDE techniques to support commercial nuclear reactor sustainability is expected to begin next year. This summer, the MAaD Pathway invited subject matter experts to participate in a series of workshops which developed the basis for the research plan of these DOE R&D NDE activities. This document presents the results of one of these workshops which are the DOE LWRS NDE R&D Roadmap for Reactor Pressure Vessels (RPV). These workshops made a substantial effort to coordinate the DOE NDE R&D with that already underway or planned by the Electric Power Research Institute (EPRI) and the Nuclear Regulatory Commission (NRC) through their representation at these workshops.

  18. Operational experience in underwater photogrammetry

    Science.gov (United States)

    Leatherdale, John D.; John Turner, D.

    Underwater photogrammetry has become established as a cost-effective technique for inspection and maintenance of platforms and pipelines for the offshore oil industry. A commercial service based in Scotland operates in the North Sea, USA, Brazil, West Africa and Australia. 70 mm cameras and flash units are built for the purpose and analytical plotters and computer graphics systems are used for photogrammetric measurement and analysis of damage, corrosion, weld failures and redesign of underwater structures. Users are seeking simple, low-cost systems for photogrammetric analysis which their engineers can use themselves.

  19. Underwater laser imaging system (UWLIS)

    Energy Technology Data Exchange (ETDEWEB)

    DeLong, M. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    Practical limitations with underwater imaging systems area reached when the noise in the back scattered radiation generated in the water between the imaging system and the target obscures the spatial contrast and resolution necessary for target discovery and identification. The advent of high power lasers operating in the blue-green portion of the visible spectrum (oceanic transmission window) has led to improved experimental illumination systems for underwater imaging. Range-gated and synchronously scanned devices take advantage of the unique temporal and spatial coherence properties of laser radiation, respectively, to overcome the deleterious effects of common volume back scatter.

  20. Task Allocation and Path Planning for Collaborative Autonomous Underwater Vehicles Operating through an Underwater Acoustic Network

    Directory of Open Access Journals (Sweden)

    Yueyue Deng

    2013-01-01

    Full Text Available Dynamic and unstructured multiple cooperative autonomous underwater vehicle (AUV missions are highly complex operations, and task allocation and path planning are made significantly more challenging under realistic underwater acoustic communication constraints. This paper presents a solution for the task allocation and path planning for multiple AUVs under marginal acoustic communication conditions: a location-aided task allocation framework (LAAF algorithm for multitarget task assignment and the grid-based multiobjective optimal programming (GMOOP mathematical model for finding an optimal vehicle command decision given a set of objectives and constraints. Both the LAAF and GMOOP algorithms are well suited in poor acoustic network condition and dynamic environment. Our research is based on an existing mobile ad hoc network underwater acoustic simulator and blind flooding routing protocol. Simulation results demonstrate that the location-aided auction strategy performs significantly better than the well-accepted auction algorithm developed by Bertsekas in terms of task-allocation time and network bandwidth consumption. We also demonstrate that the GMOOP path-planning technique provides an efficient method for executing multiobjective tasks by cooperative agents with limited communication capabilities. This is in contrast to existing multiobjective action selection methods that are limited to networks where constant, reliable communication is assumed to be available.

  1. Sources of underwater sound and their characterisation (abstract)

    NARCIS (Netherlands)

    Ainslie, M.A.; Jong, C.A.F. de

    2013-01-01

    After centuries of speculation, punctuated by occasional theoretical or experimental advances, the first intensive research into underwater sound took place 100 years ago, applied initially to provide advance warning of icebergs after the loss of RMS Titanic in 1912, and later to counter the U-boat

  2. Underwater noise due to precipitation

    DEFF Research Database (Denmark)

    Crum, Lawrence A.; Pumphrey, Hugh C.; Prosperetti, Andrea

    1989-01-01

    In 1959, G. Franz published a thorough investigation of the underwater sound produced by liquid drop impacts [G. Franz, J. Acoust. Soc. Am. 31, 1080 (1959)]. He discovered that, under certain conditions, a gas bubble was entrained by the impacting droplet, and the subsequent oscillation of this b...

  3. Underwater Robots Surface in Utah

    Science.gov (United States)

    Hurd, Randy C.; Hacking, Kip S.; Damarjian, Jennifer L.; Wright, Geoffrey A.; Truscott, Tadd

    2015-01-01

    Underwater robots (or ROVs: Remotely Operated Vehicles as they are typically called in industry) have recently become a very popular instructional STEM activity. Nationally, ROVs have been used in science and technology classrooms for several years in cities such as Seattle, San Diego, Virginia Beach, and other coastal areas. In the past two…

  4. Status on underwater plasma arc cutting in KHI, 3

    International Nuclear Information System (INIS)

    Abe, Tadashi; Aota, Toshiichi; Nishizaki, Tadashi; Nakayama, Shigeru; Yamashita, Seiji

    1983-01-01

    In Kawasaki Heavy Industries, Ltd., the development of a remote dismantling system by underwater plasma arc cutting process has been advanced, expecting its application to the dismantling and removal of nuclear reactor facilities. In the previous two reports, the fundamental experimental results such as the comparison of the cutting capability in air and in water were shown, but this time, the remote automatic cutting of wedge-shaped specimens was carried out, using a newly installed manipulator for underwater works, therefore its outline is reported. Also the cutting experiment by overhead position and vertical position was performed by using the same equipment, and comparison was made with the cutting capability by downhand and horizontal positions. It is important to grasp the cutting characteristics in the case of upward advancing and downward advancing cuttings by overhead and vertical positions when the cutting of pressure vessels and horizontal pipes into rings is supposed. The experimental apparatus, the cutting conditions, the testing method and the test results of the cutting capability test, the test of changing direction during cutting, and the remote cutting of pipes into rings are described. The underwater plasma arc cutting can cut all metals, the cutting speed is relatively high, and the apparatus is simple and compact. (Kako, I.)

  5. User's manual and analysis methodology of probabilistic fracture mechanics analysis code PASCAL Ver.2 for reactor pressure vessel (Contract research)

    International Nuclear Information System (INIS)

    Osakabe, Kazuya; Onizawa, Kunio; Shibata, Katsuyuki; Kato, Daisuke

    2006-09-01

    As a part of the aging structural integrity research for LWR components, the probabilistic fracture mechanics (PFM) analysis code PASCAL (PFM Analysis of Structural Components in Aging LWR) has been developed in JAEA. This code evaluates the conditional probabilities of crack initiation and fracture of a reactor pressure vessel (RPV) under transient conditions such as pressurized thermal shock (PTS). The development of the code has been aimed to improve the accuracy and reliability of analysis by introducing new analysis methodologies and algorithms considering the recent development in the fracture mechanics and computer performance. PASCAL Ver.1 has functions of optimized sampling in the stratified Monte Carlo simulation, elastic-plastic fracture criterion of the R6 method, crack growth analysis models for a semi-elliptical crack, recovery of fracture toughness due to thermal annealing and so on. Since then, under the contract between the Ministry of Economy, Trading and Industry of Japan and JAEA, we have continued to develop and introduce new functions into PASCAL Ver.2 such as the evaluation method for an embedded crack, K I database for a semi-elliptical crack considering stress discontinuity at the base/cladding interface, PTS transient database, and others. A generalized analysis method is proposed on the basis of the development of PASCAL Ver.2 and results of sensitivity analyses. Graphical user interface (GUI) including a generalized method as default values has been also developed for PASCAL Ver.2. This report provides the user's manual and theoretical background of PASCAL Ver.2. (author)

  6. Development of outcome measures for large-vessel vasculitis for use in clinical trials: opportunities, challenges, and research agenda.

    Science.gov (United States)

    Direskeneli, Haner; Aydin, Sibel Z; Kermani, Tanaz A; Matteson, Eric L; Boers, Maarten; Herlyn, Karen; Luqmani, Raashid A; Neogi, Tuhina; Seo, Philip; Suppiah, Ravi; Tomasson, Gunnar; Merkel, Peter A

    2011-07-01

    Giant cell (GCA) and Takayasu's arteritis (TAK) are 2 forms of large-vessel vasculitis (LVV) that involve the aorta and its major branches. GCA has a predilection for the cranial branches, while TAK tends to affect the extracranial branches. Both disorders may also cause nonspecific constitutional symptoms. Although some clinical features are more common in one or the other disorder and the ages of initial presentation differ substantially, there is enough clinical and histopathologic overlap between these disorders that some investigators suggest GCA and TAK may be 2 processes within the spectrum of a single disease. There have been few randomized therapeutic trials completed in GCA, and none in TAK. The lack of therapeutic trials in LVV is only partially explained by the rarity of these diseases. It is likely that the lack of well validated outcome measures for LVV and uncertainties regarding trial design contribute to the paucity of trials for these diseases. An initiative to develop a core set of outcome measures for use in clinical trials of LVV was launched by the international OMERACT Vasculitis Working Group in 2009 and subsequently endorsed by the OMERACT community at the OMERACT 10 meeting. Aims of this initiative include: (1) to review the literature and existing data related to outcome assessments in LVV; (2) to obtain the opinion of experts and patients on disease content; and (3) to formulate a research agenda to facilitate a more data-based approach to outcomes development.

  7. Testing a polarimetric cloud imager aboard research vessel Polarstern: comparison of color-based and polarimetric cloud detection algorithms.

    Science.gov (United States)

    Barta, András; Horváth, Gábor; Horváth, Ákos; Egri, Ádám; Blahó, Miklós; Barta, Pál; Bumke, Karl; Macke, Andreas

    2015-02-10

    Cloud cover estimation is an important part of routine meteorological observations. Cloudiness measurements are used in climate model evaluation, nowcasting solar radiation, parameterizing the fluctuations of sea surface insolation, and building energy transfer models of the atmosphere. Currently, the most widespread ground-based method to measure cloudiness is based on analyzing the unpolarized intensity and color distribution of the sky obtained by digital cameras. As a new approach, we propose that cloud detection can be aided by the additional use of skylight polarization measured by 180° field-of-view imaging polarimetry. In the fall of 2010, we tested such a novel polarimetric cloud detector aboard the research vessel Polarstern during expedition ANT-XXVII/1. One of our goals was to test the durability of the measurement hardware under the extreme conditions of a trans-Atlantic cruise. Here, we describe the instrument and compare the results of several different cloud detection algorithms, some conventional and some newly developed. We also discuss the weaknesses of our design and its possible improvements. The comparison with cloud detection algorithms developed for traditional nonpolarimetric full-sky imagers allowed us to evaluate the added value of polarimetric quantities. We found that (1) neural-network-based algorithms perform the best among the investigated schemes and (2) global information (the mean and variance of intensity), nonoptical information (e.g., sun-view geometry), and polarimetric information (e.g., the degree of polarization) improve the accuracy of cloud detection, albeit slightly.

  8. Development of a tentacle propulsion technique for underwater application

    International Nuclear Information System (INIS)

    Alamgir, T; Rashid, M M; Khan, M R

    2013-01-01

    As robotic technology matures and more platforms are fielded in unstructured real-world situations, the more new areas of applications are being thought for robotic deployment. After successes in industrial robots, researchers are now trying to explore new robots with biological features of different biological creatures like, snake, bird, and spider for their stunning advantages. Underwater exploration using robots is a new avenue. Research on the tentacle robot for underwater application is a new field of research besides the other research in this arena. There are few researches on this topic are explored and mostly are on biological robot. Besides those researches this paper aims to propose and demonstrate another technique to build a tentacle for propulsion purposes. Therefore, in this paper will discuss more on mathematical development for the propulsion technique and its software verification technique in considering the environmental constrains

  9. Final report for the 'Melt-Vessel Interactions' Project. European Union R and TD Program 4th Framework. MVI project final research report

    Energy Technology Data Exchange (ETDEWEB)

    Sehgal, B.R.; Dinh, T.N.; Nourgaliev, R.R.; Bui, V.A.; Green, J.; Kolb, G.; Karbojian, A.; Theerthan, S.A.; Gubaidulline, A. [Royal Inst. of Tech., Stockholm (Sweden). Div. of Nuclear Power Safety; Helle, M.; Kymaelaeinen, O.; Tuomisto, H. [IVO Power Engineering Ltd., Vantaa (Finland); Bonnet, J.M.; Rouge, S.; Narcoux, M.; Liegeois, A. [CEA - Grenoble (France); Turland, B.D.; Dobson, G.P. [AEA Technology plc, Dorchester (United Kingdom); Siccama, A. [ECN Nuclear Research, Petten (Netherlands); Ikonen, K. [VTT Energy, Helsinki (Finland); Parozzi, F. [ENEL - SRI/PAM/GRA, Segrate, MI (Italy); Kolev, N. [Siemens AG, Erlangen (Germany); Caira, M. [Univ. of Roma (Italy)

    1999-04-01

    The Melt Vessel Interaction (MVI) project is concerned with the consequences of the interactions that a core melt, generated during a postulated severe accident in a light water reactor, may have with the pressure vessel. In particular, the issues concerned with the failure of the vessel bottom head are the focus of the research. The specific objectives of the project are to obtain data and develop validated models, which could be applied to prototypic plants, and accident conditions, for resolution of issues related to the melt vessel interactions. The project work has been performed by nine partners having varied responsibility. The work included a large number of experiments, with simulant materials, whose observations and results are employed, respectively, to understand the physical mechanisms and to develop validated models. Applications to the prototypic geometry and conditions have also been performed. This report is volume 1 of the Final Report for the Project, in which a summary of the progress achieved in the experimental program is provided. We have, however, included some aspects of the modeling activities. Volume 2 of the Final report describes the progress achieved in the modeling program. The progress achieved in the experimental and modeling parts of the Project has led to the resolution of some of the issues of melt vessel interaction. Considerable progress was also achieved towards resolution of the remaining issues.

  10. Final report for the 'Melt-Vessel Interactions' Project. European Union R and TD Program 4th Framework. MVI project final research report

    International Nuclear Information System (INIS)

    Sehgal, B.R.; Dinh, T.N.; Nourgaliev, R.R.; Bui, V.A.; Green, J.; Kolb, G.; Karbojian, A.; Theerthan, S.A.; Gubaidulline, A.; Bonnet, J.M.; Rouge, S.; Narcoux, M.; Liegeois, A.; Turland, B.D.; Dobson, G.P.; Siccama, A.; Ikonen, K.; Parozzi, F.; Kolev, N.; Caira, M.

    1999-04-01

    The Melt Vessel Interaction (MVI) project is concerned with the consequences of the interactions that a core melt, generated during a postulated severe accident in a light water reactor, may have with the pressure vessel. In particular, the issues concerned with the failure of the vessel bottom head are the focus of the research. The specific objectives of the project are to obtain data and develop validated models, which could be applied to prototypic plants, and accident conditions, for resolution of issues related to the melt vessel interactions. The project work has been performed by nine partners having varied responsibility. The work included a large number of experiments, with simulant materials, whose observations and results are employed, respectively, to understand the physical mechanisms and to develop validated models. Applications to the prototypic geometry and conditions have also been performed. This report is volume 1 of the Final Report for the Project, in which a summary of the progress achieved in the experimental program is provided. We have, however, included some aspects of the modeling activities. Volume 2 of the Final report describes the progress achieved in the modeling program. The progress achieved in the experimental and modeling parts of the Project has led to the resolution of some of the issues of melt vessel interaction. Considerable progress was also achieved towards resolution of the remaining issues

  11. Proceedings of the 3rd international conference on heat exchangers, boilers and pressure vessels (HEB-97). Vol.1 (Research Papers)

    International Nuclear Information System (INIS)

    1997-04-01

    This conference was held on 5-6 Apr 1997 in Alexandria. the specialists discussed heat exchangers, boilers and pressure vessels. more than 200 papers were presented in the meetings. it contains of data, figures and tables

  12. Proceedings of the 3rd international conference on heat exchangers, boilers and pressure vessels (HEB-97). Vol.1 (Research Papers)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-04-01

    This conference was held on 5-6 Apr 1997 in Alexandria. the specialists discussed heat exchangers, boilers and pressure vessels. more than 200 papers were presented in the meetings. it contains of data, figures and tables.

  13. Underwater Optical Wireless Communications, Networking, and Localization: A Survey

    KAUST Repository

    Saeed, Nasir; Celik, Abdulkadir; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

    2018-01-01

    Underwater wireless communications can be carried out through acoustic, radio frequency (RF), and optical waves. Compared to its bandwidth limited acoustic and RF counterparts, underwater optical wireless communications (UOWCs) can support higher data rates at low latency levels. However, severe aquatic channel conditions (e.g., absorption, scattering, turbulence, etc.) pose great challenges for UOWCs and significantly reduce the attainable communication ranges, which necessitates efficient networking and localization solutions. Therefore, we provide a comprehensive survey on the challenges, advances, and prospects of underwater optical wireless networks (UOWNs) from a layer by layer perspective which includes: 1) Potential network architectures; 2) Physical layer issues including propagation characteristics, channel modeling, and modulation techniques 3) Data link layer problems covering link configurations, link budgets, performance metrics, and multiple access schemes; 4) Network layer topics containing relaying techniques and potential routing algorithms; 5) Transport layer subjects such as connectivity, reliability, flow and congestion control; 6) Application layer goals and state-of-the-art UOWN applications, and 7) Localization and its impacts on UOWN layers. Finally, we outline the open research challenges and point out the future directions for underwater optical wireless communications, networking, and localization research.

  14. Underwater Optical Wireless Communications, Networking, and Localization: A Survey

    KAUST Repository

    Saeed, Nasir

    2018-02-28

    Underwater wireless communications can be carried out through acoustic, radio frequency (RF), and optical waves. Compared to its bandwidth limited acoustic and RF counterparts, underwater optical wireless communications (UOWCs) can support higher data rates at low latency levels. However, severe aquatic channel conditions (e.g., absorption, scattering, turbulence, etc.) pose great challenges for UOWCs and significantly reduce the attainable communication ranges, which necessitates efficient networking and localization solutions. Therefore, we provide a comprehensive survey on the challenges, advances, and prospects of underwater optical wireless networks (UOWNs) from a layer by layer perspective which includes: 1) Potential network architectures; 2) Physical layer issues including propagation characteristics, channel modeling, and modulation techniques 3) Data link layer problems covering link configurations, link budgets, performance metrics, and multiple access schemes; 4) Network layer topics containing relaying techniques and potential routing algorithms; 5) Transport layer subjects such as connectivity, reliability, flow and congestion control; 6) Application layer goals and state-of-the-art UOWN applications, and 7) Localization and its impacts on UOWN layers. Finally, we outline the open research challenges and point out the future directions for underwater optical wireless communications, networking, and localization research.

  15. Underwater noise pollution in a coastal tropical environment.

    Science.gov (United States)

    Bittencourt, L; Carvalho, R R; Lailson-Brito, J; Azevedo, A F

    2014-06-15

    Underwater noise pollution has become a major concern in marine habitats. Guanabara Bay, southeastern Brazil, is an impacted area of economic importance with constant vessel traffic. One hundred acoustic recording sessions took place over ten locations. Sound sources operating within 1 km radius of each location were quantified during recordings. The highest mean sound pressure level near the surface was 111.56±9.0 dB re 1 μPa at the frequency band of 187 Hz. Above 15 kHz, the highest mean sound pressure level was 76.21±8.3 dB re 1 μPa at the frequency 15.89 kHz. Noise levels correlated with number of operating vessels and vessel traffic composition influenced noise profiles. Shipping locations had the highest noise levels, while small vessels locations had the lowest noise levels. Guanabara Bay showed noise pollution similar to that of other impacted coastal regions, which is related to shipping and vessel traffic. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Heat dissipation research on the water-cooling channel of HL-2M in-vessel coils

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, J., E-mail: jiangjiaming@swip.ac.cn; Liu, Y.; Chen, Q.; Ji, X.Q.

    2017-04-15

    Highlights: • The joule heat of in-vessel coils is very difficult to dissipate inside HL-2M vacuum vessel. • Heat dissipation model of the coil includes the joule heat model, the heat conduction model and the heat transfer model. • The CFD analysis has been done for the coil-water cooling, with comparison with the date of theoretical analysis and experiment. • The result shows water-cooling channel is good for the joule heat transfer and taken away. - Abstract: HL-2M in-vessel coils are positioned in high vacuum circumstance, and they will generate joule heat when they carry 15 kA electrical current, but joule heat is very difficult to dissipate in vacuum, so a hollow cable with 8 mm inner diameter is design as water-cooling channel for heat convection. By using the methods of the theoretical derivation, together with CFD numeric simulation method and the experiment of the heat transfer, the water channel of HL-2M in-vessel coils has been studied, and the temperature of HL-2M in-vessel coils under different cooling water flow rates is obtained and acceptable. Simultaneously, the external cooling water supply system parameters for the water-cooling channel of the coils are estimated. Three methods’ results are in good agreement; the theoretical model is verified and could be popularized for predicting the temperature rise of HL-2M in-vessel coils.

  17. Energy balance during underwater implosion of ductile metallic cylinders.

    Science.gov (United States)

    Chamberlin, Ryan E; Guzas, Emily L; Ambrico, Joseph M

    2014-11-01

    Energy-based metrics are developed and applied to a numerical test case of implosion of an underwater pressure vessel. The energy metrics provide estimates of the initial energy in the system (potential energy), the energy released into the fluid as a pressure pulse, the energy absorbed by the imploding structure, and the energy absorbed by air trapped within the imploding structure. The primary test case considered is the implosion of an aluminum cylinder [diameter: 2.54 cm (1 in.), length: 27.46 cm (10.81 in.)] that collapses flat in a mode-2 shape with minimal fracture. The test case indicates that the structure absorbs the majority (92%) of the initial energy in the system. Consequently, the energy emitted as a pressure pulse into the fluid is a small fraction, approximately 5%, of the initial energy. The energy absorbed by the structure and the energy emitted into the fluid are calculated for additional simulations of underwater pressure vessel implosions. For all cases investigated, there is minimal fracture in the collapse, the structure absorbs more than 80% of the initial energy of the system, and the released pressure pulse carries away less than 6% of the initial energy.

  18. In-vessel tritium

    International Nuclear Information System (INIS)

    Ueda, Yoshio; Ohya, Kaoru; Ashikawa, Naoko; Ito, Atsushi M.; Kato, Daiji; Kawamura, Gakushi; Takayama, Arimichi; Tomita, Yukihiro; Nakamura, Hiroaki; Ono, Tadayoshi; Kawashima, Hisato; Shimizu, Katsuhiro; Takizuka, Tomonori; Nakano, Tomohide; Nakamura, Makoto; Hoshino, Kazuo; Kenmotsu, Takahiro; Wada, Motoi; Saito, Seiki; Takagi, Ikuji; Tanaka, Yasunori; Tanabe, Tetsuo; Yoshida, Masafumi; Toma, Mitsunori; Hatayama, Akiyoshi; Homma, Yuki; Tolstikhina, Inga Yu.

    2012-01-01

    The in-vessel tritium research is closely related to the plasma-materials interaction. It deals with the edge-plasma-wall interaction, the wall erosion, transport and re-deposition of neutral particles and the effect of neutral particles on the fuel recycling. Since the in-vessel tritium shows a complex nonlinear behavior, there remain many unsolved problems. So far, behaviors of in-vessel tritium have been investigated by two groups A01 and A02. The A01 group performed experiments on accumulation and recovery of tritium in thermonuclear fusion reactors and the A02 group studied theory and simulation on the in-vessel tritium behavior. In the present article, outcomes of the research are reviewed. (author)

  19. DE-Sync: A Doppler-Enhanced Time Synchronization for Mobile Underwater Sensor Networks.

    Science.gov (United States)

    Zhou, Feng; Wang, Qi; Nie, DongHu; Qiao, Gang

    2018-05-25

    Time synchronization is the foundation of cooperative work among nodes of underwater sensor networks; it takes a critical role in the research and application of underwater sensor networks. Although numerous time synchronization protocols have been proposed for terrestrial wireless sensor networks, they cannot be directly applied to underwater sensor networks. This is because most of them typically assume that the propagation delay among sensor nodes is negligible, which is not the case in underwater sensor networks. Time synchronization is mainly affected by a long propagation delay among sensor nodes due to the low propagation speed of acoustic signals. Furthermore, sensor nodes in underwater tend to experience some degree of mobility due to wind or ocean current, or some other nodes are on self-propelled vehicles, such as autonomous underwater vehicles (AUVs). In this paper, we propose a Doppler-enhanced time synchronization scheme for mobile underwater sensor networks, called DE-Sync. Our new scheme considers the effect of the clock skew during the process of estimating the Doppler scale factor and directly substitutes the Doppler scale factor into linear regression to achieve the estimation of the clock skew and offset. Simulation results show that DE-Sync outperforms existing time synchronization protocols in both accuracy and energy efficiency.

  20. Cutting method and device underwater

    International Nuclear Information System (INIS)

    Takano, Genta; Kamei, Hiromasa; Beppu, Seiji

    1998-01-01

    A place of material to be cut is surrounded by an openable/closable box. The material to be cut is cut underwater, and materials generated in this case are removed from the cut portion by a pressurized water jet. The removed materials are sucked and recovered together with water in the box. Among the materials caused by the cutting underwater, solid materials not floating on water are caused to stay in the midway of a sucking and recovering channel. A large sucking force might be required for the entire region of the sucking and recovering channel when sucking and recovering large sized solid materials not floating on water, but even large sized materials can be recovered easily according to the present invention since they are recovered after being sucked and stayed in the midway of the sucking and recovering channel. (N.H.)

  1. Tracking the position of the underwater robot for nuclear reactor inspection

    International Nuclear Information System (INIS)

    Jeo, J. W.; Kim, C. H.; Seo, Y. C.; Choi, Y. S.; Kim, S. H.

    2003-01-01

    The tracking procedure of the underwater mobile robot moving and submerging ahead to nuclear reactor vessel for visual inspection, which is required to find the foreign objects such as loose parts, is described. The yellowish underwater robot body tends to present a big contrast to boron solute cold water of nuclear reactor vessel, tinged with indigo by the Cerenkov effect. In this paper, we have found and tracked the positions of underwater mobile robot using the two color information, yellow and indigo. From the horizontal and vertical profiles analysis of the color image, the blue, green, and the gray component have the inferior signal-to-noise characteristics compared to the red component. The center coordinates extraction procedures areas follows. The first step is to segment the underwater robot body to cold water with indigo background. From the RGB color components of the entire monitoring image taken with the color CCD camera, we have selected the red color component. In the selected red image, we extracted the positions of the underwater mobile robot using the following process sequences; binarization, labelling, and centroid extraction techniques. In the experiment carried out at the Youngkwang unit 5 nuclear reactor vessel, we have tracked the center positions of the underwater robot submerged near the cold leg and the hot leg way, which is fathomed to 10m deep in depth. When the position of the robot vehicle fluctuates between the previous and the current image frame due to the flickering noise and light source, installed temporally in the bottom of the reactor vessel, we adaptively adjusted the ROI window. Adding the ROI windows of the previous frame to the current frame, and then setting up the ROI window of the next image frame, we can robustly track the positions of the underwater robot and control the target position's divergence. From these facts, we can conclude that using the red component from color camera is more efficient tracking method

  2. Evaluation of Underwater Image Enhancement Algorithms under Different Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Marino Mangeruga

    2018-01-01

    Full Text Available Underwater images usually suffer from poor visibility, lack of contrast and colour casting, mainly due to light absorption and scattering. In literature, there are many algorithms aimed to enhance the quality of underwater images through different approaches. Our purpose was to identify an algorithm that performs well in different environmental conditions. We have selected some algorithms from the state of the art and we have employed them to enhance a dataset of images produced in various underwater sites, representing different environmental and illumination conditions. These enhanced images have been evaluated through some quantitative metrics. By analysing the results of these metrics, we tried to understand which of the selected algorithms performed better than the others. Another purpose of our research was to establish if a quantitative metric was enough to judge the behaviour of an underwater image enhancement algorithm. We aim to demonstrate that, even if the metrics can provide an indicative estimation of image quality, they could lead to inconsistent or erroneous evaluations.

  3. QFD-based conceptual design of an autonomous underwater robot

    Directory of Open Access Journals (Sweden)

    Thip Pasawang

    2015-12-01

    Full Text Available Autonomous underwater robots in the past few years have been designed according to the individual concepts and experiences of the researchers. To design a robot, which meets all the requirements of potential users, is an advanced work. Hence, a systematic design method that could include users’ preferences and requirements is needed. This paper presents the quality function deployment (QFD technique to design an autonomous underwater robot focusing on the Thai Navy military mission. Important user requirements extracted from the QFD method are the ability to record videos, operating at depth up to 10 meters, the ability to operate remotely with cable and safety concerns related to water leakages. Less important user requirements include beauty, using renewable energy, operating remotely with radio and ability to work during night time. The important design parameters derived from the user requirements are a low cost-controller, an autonomous control algorithm, a compass sensor and vertical gyroscope, and a depth sensor. Of low-importance ranked design parameters include the module design, use clean energy, a low noise electric motor, remote surveillance design, a pressure hull, and a beautiful hull form design. The study results show the feasibility of using QFD techniques to systematically design the autonomous underwater robot to meet user requirements. Mapping between the design and expected parameters and a conceptual drafting design of an autonomous underwater robot are also presented.

  4. Development of a highly maneuverable unmanned underwater vehicle on the basis of quad-copter dynamics

    Science.gov (United States)

    Amin, Osman Md; Karim, Md. Arshadul; Saad, Abdullah His

    2017-12-01

    At present, research on unmanned underwater vehicle (UUV) has become a significant & familiar topic for researchers from various engineering fields. UUV is of mainly two types - AUV (Autonomous Underwater vehicle) & ROV (Remotely Operated Vehicle). There exist a significant number of published research papers on UUV, where very few researchers emphasize on the ease of maneuvering and control of UUV. Maneuvering is important for underwater vehicle in avoiding obstacles, installing underwater piping system, searching undersea resources, underwater mine disposal operations, oceanographic surveys etc. A team from Dept. of Naval Architecture & Marine Engineering of MIST has taken a project to design a highly maneuverable unmanned underwater vehicle on the basis of quad-copter dynamics. The main objective of the research is to develop a control system for UUV which would be able to maneuver the vehicle in six DOF (Degrees of Freedom) with great ease. For this purpose we are not only focusing on controllability but also designing an efficient hull with minimal drag force & optimized propeller using CFD technique. Motors were selected on the basis of the simulated thrust generated by propellers in ANSYS Fluent software module. Settings for control parameters to carry out different types of maneuvering such as hovering, spiral, one point rotation about its centroid, gliding, rolling, drifting and zigzag motions were explained in short at the end.

  5. Developing a Computational Environment for Coupling MOR Data, Maps, and Models: The Virtual Research Vessel (VRV) Prototype

    Science.gov (United States)

    Wright, D. J.; O'Dea, E.; Cushing, J. B.; Cuny, J. E.; Toomey, D. R.; Hackett, K.; Tikekar, R.

    2001-12-01

    The East Pacific Rise (EPR) from 9-10deg. N is currently our best-studied section of fast-spreading mid-ocean ridge. During several decades of investigation it has been explored by the full spectrum of ridge investigators, including chemists, biologists, geologists and geophysicists. These studies, and those that are ongoing, provide a wealth of observational data, results and data-driven theoretical (often numerical) studies that have not yet been fully utilized either by research scientists or by professional educators. While the situation is improving, a large amount of data, results, and related theoretical models still exist either in an inert, non-interactive form (e.g., journal publications) or as unlinked and currently incompatible computer data or algorithms. Infrastructure is needed not just for ready access to data, but linkage of disparate data sets (data to data) as well as data to models in order quantitatively evaluate hypotheses, refine numerical simulations, and explore new relations between observables. The prototype of a computational environment and toolset, called the Virtual Research Vessel (VRV), is being developed to provide scientists and educators with ready access to data, results and numerical models. While this effort is focused on the EPR 9N region, the resulting software tools and infrastructure should be helpful in establishing similar systems for other sections of the global mid-ocean ridge. Work in progress includes efforts to develop: (1) virtual database to incorporate diverse data types with domain-specific metadata into a global schema that allows web-query across different marine geology data sets, and an analogous declarative (database available) description of tools and models; (2) the ability to move data between GIS and the above DBMS, and tools to encourage data submission to archivesl (3) tools for finding and viewing archives, and translating between formats; (4) support for "computational steering" (tool composition

  6. OPTICAL correlation identification technology applied in underwater laser imaging target identification

    Science.gov (United States)

    Yao, Guang-tao; Zhang, Xiao-hui; Ge, Wei-long

    2012-01-01

    The underwater laser imaging detection is an effective method of detecting short distance target underwater as an important complement of sonar detection. With the development of underwater laser imaging technology and underwater vehicle technology, the underwater automatic target identification has gotten more and more attention, and is a research difficulty in the area of underwater optical imaging information processing. Today, underwater automatic target identification based on optical imaging is usually realized with the method of digital circuit software programming. The algorithm realization and control of this method is very flexible. However, the optical imaging information is 2D image even 3D image, the amount of imaging processing information is abundant, so the electronic hardware with pure digital algorithm will need long identification time and is hard to meet the demands of real-time identification. If adopt computer parallel processing, the identification speed can be improved, but it will increase complexity, size and power consumption. This paper attempts to apply optical correlation identification technology to realize underwater automatic target identification. The optics correlation identification technology utilizes the Fourier transform characteristic of Fourier lens which can accomplish Fourier transform of image information in the level of nanosecond, and optical space interconnection calculation has the features of parallel, high speed, large capacity and high resolution, combines the flexibility of calculation and control of digital circuit method to realize optoelectronic hybrid identification mode. We reduce theoretical formulation of correlation identification and analyze the principle of optical correlation identification, and write MATLAB simulation program. We adopt single frame image obtained in underwater range gating laser imaging to identify, and through identifying and locating the different positions of target, we can improve

  7. Underwater Coatings for Contamination Control

    International Nuclear Information System (INIS)

    Julia L. Tripp; Kip Archibald; Ann-Marie Phillips; Joseph Campbell

    2004-01-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) is deactivating several fuel storage basins. Airborne contamination is a concern when the sides of the basins are exposed and allowed to dry during water removal. One way of controlling this airborne contamination is to fix the contamination in place while the pool walls are still submerged. There are many underwater coatings available on the market that are used in marine, naval and other applications. A series of tests were run to determine whether the candidate underwater fixatives are easily applied and adhere well to the substrates (pool wall materials) found in INEEL fuel pools. The four pools considered included (1) Test Area North (TAN-607) with epoxy painted concrete walls; (2) Idaho Nuclear Technology and Engineering Center (INTEC) (CPP-603) with bare concrete walls; (3) Materials Test Reactor (MTR) Canal with stainless steel lined concrete walls; and (4) Power Burst Facility (PBF-620) with stainless steel lined concrete walls on the bottom and epoxy painted carbon steel lined walls on the upper portions. Therefore, the four materials chosen for testing included bare concrete, epoxy painted concrete, epoxy painted carbon steel, and stainless steel. The typical water temperature of the pools varies from 55 F to 80 F dependent on the pool and the season. These tests were done at room temperature. The following criteria were used during this evaluation. The underwater coating must: (1) Be easy to apply; (2) Adhere well to the four surfaces of interest; (3) Not change or have a negative impact on water chemistry or clarity; (4) Not be hazardous in final applied form; and (5) Be proven in other underwater applications. In addition, it is desirable for the coating to have a high pigment or high cross-link density to prevent radiation from penetrating. This paper will detail the testing completed and the test results. A proprietary two-part, underwater epoxy owned by S. G. Pinney and Associates

  8. Underwater Acoustic Signal Processing

    National Research Council Canada - National Science Library

    Culver, Richard L; Sibul, Leon H; Bradley, David L

    2007-01-01

    .... The research is directed toward passive sonar detection and classification, continuous wave (CW) and broadband signals, shallow water operation, both platform-mounted and distributed systems, and frequencies below 1 kHz...

  9. Long Term Validation of High Precision RTK Positioning Onboard a Ferry Vessel Using the MGBAS in the Research Port of Rostock

    Directory of Open Access Journals (Sweden)

    Ralf Ziebold

    2017-09-01

    Full Text Available In order to enable port operations, which require an accuracy of about 10cm, the German Aerospace Center (DLR operates the Maritime Ground Based Augmentation Service (MGBAS in the Research Port of Rostock. The MGBAS reference station provides GPS dual frequency code + phase correction data, which are continuously transmitted via an ultra-high frequency (UHF modem. Up to now the validation of the MGBAS was rather limited. Either a second shore based station was used as an artificial user, or measurement campaigns on a vessel with duration of a few hours have been conducted. In order to overcome this, we have installed three separate dual frequency antennas and receivers and a UHF modem on the Stena Line ferry vessel Mecklenburg-Vorpommern which is plying between Rostock and Trelleborg. This paper concentrates on the analysis of the highly accurate phase based positioning with a Real Time Kinematic (RTK algorithm, using correction data received by the UHF modem onboard the vessel. We analyzed the availability and accuracy of RTK fix solutions for several days, whenever the ferry vessel was inside the service area of the MGBAS.

  10. Antibody-linked drug destroys tumor cells and tumor blood vessels in many types of cancer | Center for Cancer Research

    Science.gov (United States)

    A team led by Brad St. Croix, Ph.D., Senior Associate Scientist, Mouse Cancer Genetics Program, has developed an antibody-drug conjugate (ADC) that destroys both tumor cells and the blood vessels that nourish them. The drug significantly shrank breast tumors, colon tumors and several other types of cancer and prolonged survival. Learn more...  

  11. Investigation of the Propagation Characteristics of Underwater Shock Waves in Underwater Drilling Blasting

    Directory of Open Access Journals (Sweden)

    Xin Liu

    2018-01-01

    Full Text Available During the first-stage project of the main channel of Ningbo-Zhoushan Port’s Shipu Harbor, underwater shock waves were monitored. By analyzing a typical measured pressure time history curve, the characteristics of underwater shock waves in an engineering context were obtained. We obtained a traditional exponential attenuation formula for underwater shock waves based on the measured data, simplified the model of underwater drilling blasting based on engineering practice, deduced a revised formula for underwater shock wave peak overpressure on the basis of dimensional analysis, established a linear fitting model, and obtained the undetermined coefficients of the revised formula using a linear regression analysis. In addition, the accuracies of the two formulas used to predict underwater shock wave peak overpressure and the significance order of influence and influence mechanism of factors included in the revised formula on the underwater shock wave peak overpressure were discussed.

  12. Priority Determination of Underwater Tourism Site Development in Gorontalo Province using Analytical Hierarchy Process (AHP)

    Science.gov (United States)

    Rohandi, M.; Tuloli, M. Y.; Jassin, R. T.

    2018-02-01

    This research aims to determine the development of priority of underwater tourism in Gorontalo province using the Analytical Hierarchy Process (AHP) method which is one of DSS methods applying Multi-Attribute Decision Making (MADM). This method used 5 criteria and 28 alternatives to determine the best priority of underwater tourism site development in Gorontalo province. Based on the AHP calculation it appeared that the best priority development of underwater tourism site is Pulau Cinta whose total AHP score is 0.489 or 48.9%. This DSS produced a reliable result, faster solution, time-saving, and low cost for the decision makers to obtain the best underwater tourism site to be developed.

  13. ROV Based Underwater Blurred Image Restoration

    Institute of Scientific and Technical Information of China (English)

    LIU Zhishen; DING Tianfu; WANG Gang

    2003-01-01

    In this paper, we present a method of ROV based image processing to restore underwater blurry images from the theory of light and image transmission in the sea. Computer is used to simulate the maximum detection range of the ROV under different water body conditions. The receiving irradiance of the video camera at different detection ranges is also calculated. The ROV's detection performance under different water body conditions is given by simulation. We restore the underwater blurry images using the Wiener filter based on the simulation. The Wiener filter is shown to be a simple useful method for underwater image restoration in the ROV underwater experiments. We also present examples of restored images of an underwater standard target taken by the video camera in these experiments.

  14. Quantum imaging for underwater arctic navigation

    Science.gov (United States)

    Lanzagorta, Marco

    2017-05-01

    The precise navigation of underwater vehicles is a difficult task due to the challenges imposed by the variable oceanic environment. It is particularly difficult if the underwater vehicle is trying to navigate under the Arctic ice shelf. Indeed, in this scenario traditional navigation devices such as GPS, compasses and gyrocompasses are unavailable or unreliable. In addition, the shape and thickness of the ice shelf is variable throughout the year. Current Arctic underwater navigation systems include sonar arrays to detect the proximity to the ice. However, these systems are undesirable in a wartime environment, as the sound gives away the position of the underwater vehicle. In this paper we briefly describe the theoretical design of a quantum imaging system that could allow the safe and stealthy navigation of underwater Arctic vehicles.

  15. LAKE BAIKAL: Underwater neutrino detector

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    A new underwater detector soon to be deployed in Lake Baikal in Siberia, the world's deepest lake with depths down to 1.7 kilometres, could help probe the deepest mysteries of physics. One of the big unsolved problems of astrophysics is the origin of very energetic cosmic rays. However there are many ideas on how particles could be accelerated by exotic concentrations of matter and provide the majority of the Galaxy's high energy particles. Clarification would come from new detectors picking up the energetic photons and neutrinos from these sources

  16. Underwater Electrical Safety Practices

    Science.gov (United States)

    1976-01-01

    Raferty, E.B., et al.,"Disturbances of Heart Rhythm Pro- duced by 50 Hz Leakage Current in Human Subjects," Cardio - vascular Research, Vol. 9, 1975...L 0 hii ccc 0%0 ha U.,- 1CCILJ I0 0. L N I- I 2o Cz fu*co Tc w .9000 uU ULVx C 0 L Xl 00 -Z 4 LU W UlCC cn 10. tit 0 000 coo Z CN 4- N’N hiit ww o~c

  17. Localization Algorithms of Underwater Wireless Sensor Networks: A Survey

    Science.gov (United States)

    Han, Guangjie; Jiang, Jinfang; Shu, Lei; Xu, Yongjun; Wang, Feng

    2012-01-01

    In Underwater Wireless Sensor Networks (UWSNs), localization is one of most important technologies since it plays a critical role in many applications. Motivated by widespread adoption of localization, in this paper, we present a comprehensive survey of localization algorithms. First, we classify localization algorithms into three categories based on sensor nodes’ mobility: stationary localization algorithms, mobile localization algorithms and hybrid localization algorithms. Moreover, we compare the localization algorithms in detail and analyze future research directions of localization algorithms in UWSNs. PMID:22438752

  18. Cooperative Control of Unmanned Surface Vessels and Unmanned Underwater Vessels for Asset Protection

    Science.gov (United States)

    2015-05-18

    are met as well. APPENDIX A –CODE FOR SIMPLE SURFACE PRIMARY SIMULATION % Input Variables cap desired 0.95; xd 2000; yd 2000...50 for t 1:1:50 % Capability Calculations if ((640/(2*sqrt((yd y1)^2 + ( xd x1)^2)*tand(24/2))) > 3) & ((640/(2*sqrt((yd...y2)^2 + ( xd x2)^2)*tand(24/2))) > 3) c1 1 0.0000000000000001*sqrt((yd y1)^2 + ( xd x1)^2); c2 (1 0.0000000000000001

  19. The vessel fluence; Fluence cuve

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    This book presents the proceedings of the technical meeting on the reactors vessels fluence. They are grouped in eight sessions: the industrial context and the stakes of the vessels control; the organization and the methodology for the fluence computation; the concerned physical properties; the reference computation methods; the fluence monitoring in an industrial context; vessels monitoring under irradiation; others methods in the world; the research and development programs. (A.L.B.)

  20. Displacement responses of a mysticete, an odontocete, and a phocid seal to construction-related vessel traffic

    NARCIS (Netherlands)

    Anderwald, P.; Brandecker, A.; Coleman, M.; Collins, C.; Denniston, H.; Haberlin, M.D.; O’Donovan, M.; Pinfield, R.; Visser, F.; Walshe, L.

    2013-01-01

    Marine construction works often lead to temporary increases in vessel traffic, which, in addition to the construction activity itself, contribute to underwater ambient noise in the affected area and increase the risk of vessel collision for marine mammals. Using a 3 yr data set of cliff-based

  1. Development of a submersible gravimeter on underwater vehicles

    Science.gov (United States)

    Yamada, T.; Kanazawa, T.; Fujimoto, H.; Shinohara, M.; Ishihara, T.; Araya, A.; Iizasa, K.; Tsukioka, S.

    2012-12-01

    Gravity is one of the powerful indices to profile underground structures. Surface ship gravimeters are popular tool for the purpose of collecting gravity values in marine region. They enable you to obtain gravity values from large area easily, while the resolutions are relatively low because of the distance between the sea surface and bottom. Otherwise, ocean bottom gravimeters are able to be observed gravity with high resolution, but they have still covered few limited sites so that they are designed to do observation in quiet only. In some cases, such as hydrothermal deposit survey, the medium performance both in resolution and size of survey area are required. This paper describes a gravimeter we have been developing for satisfying the requirements. Our target is to detect gravity anomalies less than 1 mgal by using an underwater vehicle. This setting is roughly equivalent to find a typical hydrothermal deposit with a dimension of 0.5 km x 0.5 km x 10 m and a density contrast of 1 g/cm3 when we set the sensor at 50 m high from the seafloor. There are some issues such as noise reduction, robustness and downsizing to clear the target. A gravity sensor (Micro-g LaCoste S-174) is mounted on a gimbal control unit with an inertial navigation sensor for the problems. These are stored in a sphere vessel made of titanium alloy (125 kgf in air, 32 kgf in water) and it is available in 3500 m below sea surface. Furthermore, in order to reduce high frequency noise due to mainly the vehicle motion through a low-pass filter, data are able to be stored at sampling rates of approximately 100 Hz. The logging system and control unit for communication to/from ship is stored another canister (22 kgf in air, 10 kgf in water). We made gravity measurement experiments to examine the effectiveness of the gimbal system and filtering application. The gravimeter was set on a machine simulating pitch and roll motions with a period of 16 s and an amplitude of 7.5 degrees, which is greater

  2. A new technique for robot vision in autonomous underwater vehicles using the color shift in underwater imaging

    Science.gov (United States)

    2017-06-01

    FOR ROBOT VISION IN AUTONOMOUS UNDERWATER VEHICLES USING THE COLOR SHIFT IN UNDERWATER IMAGING by Jake A. Jones June 2017 Thesis Advisor...techniques to determine the distances from each pixel to the camera. 14. SUBJECT TERMS unmanned undersea vehicles (UUVs), autonomous ... AUTONOMOUS UNDERWATER VEHICLES USING THE COLOR SHIFT IN UNDERWATER IMAGING Jake A. Jones Lieutenant Commander, United States Navy B.S

  3. Containment vessel

    International Nuclear Information System (INIS)

    Zbirohowski-Koscia, K.F.; Roberts, A.C.

    1980-01-01

    A concrete containment vessel for nuclear reactors is disclosed that is spherical and that has prestressing tendons disposed in first, second and third sets, the tendons of each set being all substantially concentric and centred around a respective one of the three orthogonal axes of the sphere; the tendons of the first set being anchored at each end at a first anchor rib running around a circumference of the vessel, the tendons of the second set being anchored at each end at a second anchor rib running around a circumference of the sphere and disposed at 90 0 to the first rib, and the tendons of the third set being anchored some to the first rib and the remainder to the second rib. (author)

  4. Dynamics and Control of Underwater Gliders I: Steady Motions

    OpenAIRE

    Mahmoudian, N.; Geisbert, J.; Woolsey, C.

    2007-01-01

    This paper describes analysis of steady motions for underwater gliders, a type of highly efficient underwater vehicle which uses gravity for propulsion. Underwater gliders are winged underwater vehicles which locomote by modulating their buoyancy and their attitude. Several such vehicles have been developed and have proven their worth as efficient long-distance, long-duration ocean sampling platforms. To date, the primary emphasis in underwater glider development has been on locomotive effici...

  5. Analysing deterioration of marble stones exposed to underwater conditions

    Science.gov (United States)

    Cámara, Beatriz; Álvarez de Buergo, Mónica; Bethencourt, Manuel; Freire-Lista, David; Fort, Rafael

    2016-04-01

    The peculiar conditions of the marine environment make the conservation of underwater archaeological sites an extremely complex procedure. This is due to the fact that the prevailing conditions in this environment promote the development of deterioration phenomena in submerged artefacts through the synergistic action of physical, chemical and biological factors. The objective of the present investigation was to determine how petrophysical properties of cultural heritage materials can be affected by being exposed to the specific underwater conditions of the sea bottom, and so, to evaluate how this can affect, in a long term, in their durability and evolution when they part of an archaeological site. For this purpose, two types of marble (the Italian Carrara and the Spanish Macael) were subjected to an experiment consisting of exposing stone materials for one and a half year to underwater conditions. The experimental test was located in an archaeological site in the Bay of Cadiz (southern Spain), Bajo del Chapitel (recognized as Cultural Interest), which includes remains of shipwrecks from different periods. In this site, samples were submerged to 12 m depth and placed in the sea bottom simulating the different positions in which underwater archaeological objects can be found (fully exposed, half buried and covered). Petrophysical characterisation involved determination of the apparent and bulk densities, water saturation (maximum water content a material may contain), open porosity (porosity accessible to water), chromatic parameters and ultrasonic velocity. Before measuring, samples were subjected to mechanical cleaning (in those samples with biological colonization) and to removal of salt deposits. Results showed significant differences in these petrophysical properties after underwater submersion, which were directly related to the type of underwater exposure condition. Comparative analysis of petrophysical properties, like the one conducted in this study

  6. A study on corium melt pool behavior under external vessel cooling : investigation of the first phase research results in the OECD RASPLAV project

    Energy Technology Data Exchange (ETDEWEB)

    Park, Rae Joon; Kim, Sang Baik; Kim, Hee Dong; Yoo, Kun Joong

    1998-04-01

    The scope and contents of the OECD RASPLAV program are to investigate natural convection heat transfer in the corium, chemical and mechanical interaction between the corium and the reactor vessel, crust formation of the corium, and thermal behaviour of the corium by experiments and model development during external vessel cooling to prevent reactor vessel failure in severe accidents of nuclear power plant. This study includes evaluation and analysis of the RASPLAV V phase I results for three years between July 1, 1994 and June 30, 1997. These results supply technical basis for our experimental program on severe accident research. Two large-scale experiments of RASPLAV-AW-between the corium and the reactor vessel. Several small-scale experiments were conducted to analyze thermal stratification in the corium. The salt experiments were conducted to estimate the crust and the mushy region formation, and natural convection heat transfer in the corium. In the analytical studies, pre and post analysis of the RASPLAV-AW-200 experiments and evaluation of the salt test results have been performed using CONV 2 and 3D computer codes, which were developed during RASPLAV program phase I. Low density corium was separated from the high density corium during the RASPLAV-AW-200 tests and the TULPAN test, which was a new finding in the RASPLAV project phase I. From the salts test, heat flux distribution in the side wall heating case is similar to the direct internal heat generation case, and the crust formation is a little effect on heat transfer rate. The results of CONV 2 and 3 D were very well with with the experimental results. The results of RASLAV project phase I, such as furnace design and the techniques on fuel melting, are very helpful to our severe accident experimental program. (author). 57 refs., 13 tabs., 52 figs.

  7. Visualization of vessel traffic

    NARCIS (Netherlands)

    Willems, C.M.E.

    2011-01-01

    Moving objects are captured in multivariate trajectories, often large data with multiple attributes. We focus on vessel traffic as a source of such data. Patterns appearing from visually analyzing attributes are used to explain why certain movements have occurred. In this research, we have developed

  8. Fouling in your own nest: vessel noise increases biofouling.

    Science.gov (United States)

    Stanley, Jenni A; Wilkens, Serena L; Jeffs, Andrew G

    2014-01-01

    Globally billions of dollars are spent each year on attempting to reduce marine biofouling on commercial vessels, largely because it results in higher fuel costs due to increased hydrodynamic drag. Biofouling has been long assumed to be primarily due to the availability of vacant space on the surface of the hull. Here, it is shown that the addition of the noise emitted through a vessel's hull in port increases the settlement and growth of biofouling organisms within four weeks of clean surfaces being placed in the sea. More than twice as many bryozoans, oysters, calcareous tube worms and barnacles settled and established on surfaces with vessel noise compared to those without. Likewise, individuals from three species grew significantly larger in size in the presence of vessel noise. The results demonstrate that vessel noise in port is promoting biofouling on hulls and that underwater sound plays a much wider ecological role in the marine environment than was previously considered possible.

  9. Corrosion Resistant Cladding by YAG Laser Welding in Underwater Environment

    International Nuclear Information System (INIS)

    Tsutomi Kochi; Toshio Kojima; Suemi Hirata; Ichiro Morita; Katsura Ohwaki

    2002-01-01

    It is known that stress-corrosion cracking (SCC) will occur in nickel-base alloys used in Reactor Pressure Vessel (RPV) and Internals of nuclear power plants. A SCC sensitivity has been evaluated by IHI in each part of RPV and Internals. There are several water level instrumentation nozzles installed in domestic BWR RPV. In water level instrumentation nozzles, 182 type nickel-base alloys were used for the welding joint to RPV. It is estimated the SCC potential is high in this joint because of a higher residual stress than the yield strength (about 400 MPa). This report will describe a preventive maintenance method to these nozzles Heat Affected Zone (HAZ) and welds by a corrosion resistant cladding (CRC) by YAG Laser in underwater environment (without draining a reactor water). There are many kinds of countermeasures for SCC, for example, Induction Heating Stress Improvement (IHSI), Mechanical Stress Improvement Process (MSIP) and so on. A YAG laser CRC is one of them. In this technology a laser beam is used for heat source and irradiated through an optical fiber to a base metal and SCC resistant material is used for welding wires. After cladding the HAZ and welds are coated by the corrosion resistant materials so their surfaces are improved. A CRC by gas tungsten arc welding (GTAW) in an air environment had been developed and already applied to a couple of operating plants (16 Nozzles). This method was of course good but it spent much time to perform because of an installation of some water-proof working boxes to make a TIG-weldability environment. CRC by YAG laser welding in underwater environment has superior features comparing to this conventional TIG method as follows. At the viewpoint of underwater environment, (1) an outage term reduction (no drainage water). (2) a radioactive exposure dose reduction for personnel. At that of YAG laser welding, (1) A narrower HAZ. (2) A smaller distortion. (3) A few cladding layers. A YAG laser CRC test in underwater

  10. Underwater inspection and maintenance programs within nuclear and non-nuclear related operating systems

    International Nuclear Information System (INIS)

    Vallance, C.; Goulet, B.; Black, S.

    2008-01-01

    The increasing age of the nuclear and non-nuclear power generating facilities requires extended inspection, repair and maintenance (IRM) activities to prolong the operation of these facilities past their original design life. Commercial divers are often utilized to perform critical work at nuclear power plants, fuel reprocessing plants, waste storage facilities, and research institutions. These various tasks include inspection, welding, mechanical modifications and repairs, coating applications, and work associated with plant decommissioning. Programs may take place in areas such as the reactor vessel, equipment pool, spent fuel pool, and suppression chamber using manned intervention and remotely operated vehicles. Some of these tasks can also be conducted using remotely operated vehicles (ROV's). Although specialist robots are not uncommon to the nuclear industry, the use of free-swimming vehicle's and remote systems for the inspection of underwater assets has increased due to improvements of the supporting technologies and information requirements needed to extend the life of these facilities. This paper will provide an overview of the procedures and equipment necessary to perform unique work tasks using manned and unmanned techniques. (author)

  11. Underwater Object Segmentation Based on Optical Features

    Directory of Open Access Journals (Sweden)

    Zhe Chen

    2018-01-01

    Full Text Available Underwater optical environments are seriously affected by various optical inputs, such as artificial light, sky light, and ambient scattered light. The latter two can block underwater object segmentation tasks, since they inhibit the emergence of objects of interest and distort image information, while artificial light can contribute to segmentation. Artificial light often focuses on the object of interest, and, therefore, we can initially identify the region of target objects if the collimation of artificial light is recognized. Based on this concept, we propose an optical feature extraction, calculation, and decision method to identify the collimated region of artificial light as a candidate object region. Then, the second phase employs a level set method to segment the objects of interest within the candidate region. This two-phase structure largely removes background noise and highlights the outline of underwater objects. We test the performance of the method with diverse underwater datasets, demonstrating that it outperforms previous methods.

  12. A High-Rate Virtual Instrument of Marine Vehicle Motions for Underwater Navigation and Ocean Remote Sensing

    CERN Document Server

    Gelin, Chrystel

    2013-01-01

    Dead-Reckoning aided with Doppler velocity measurement has been the most common method for underwater navigation for small vehicles. Unfortunately DR requires frequent position recalibrations and underwater vehicle navigation systems are limited to periodic position update when they surface. Finally standard Global Positioning System (GPS) receivers are unable to provide the rate or precision required when used on a small vessel. To overcome this, a low cost high rate motion measurement system for an Unmanned Surface Vehicle (USV) with underwater and oceanographic purposes is proposed. The proposed onboard system for the USV consists of an Inertial Measurement Unit (IMU) with accelerometers and rate gyros, a GPS receiver, a flux-gate compass, a roll and tilt sensor and an ADCP. Interfacing all the sensors proved rather challenging because of their different characteristics. The proposed data fusion technique integrates the sensors and develops an embeddable software package, using real time data fusion method...

  13. Simulation of the behavior of pressurized underwater concrete

    Directory of Open Access Journals (Sweden)

    Ashraf Mohamed Heniegal

    2015-06-01

    Full Text Available Under-Water Concrete (UWC contains Anti-Washout Admixtures (AWA (0.0%, 0.2%, 0.3%, 0.4% and 0.5% by weight of cement with cement contents (400, 450, 500 and 550 kg/m3. All concrete mix contains silica fume and high-range water reducing (15% and 4% respectively by weight of cement. The fine to steel slag coarse aggregate was 1:1. The concrete mix was tested for slump, slump flow, compressive strength and washout resistance using two test methods based on different principles. The first method is the plunge test CRDC61 which is widely used in North America, and the second method is the pressurized air tube which has been manufactured for this research and developed to simulate the effect of water pressure on washout resistance of underwater mix. The results of compressive strength test were compared to concrete cast underwater with that cast in air. Test results indicated that the use of an AWA facilitates the production of UWC mix with the added benefit of lower washout resistance. New technique of simulating pressurized UWC is reliable for detecting UWC properties. Adding AWA (0.3–0.5% by weight of cement makes all mix acceptable according to Japanese Society of Civil Engineers.

  14. Underwater photogrammetry successful in Spain and France

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    Underwater photogrammetry has been used to measure distortions in fuel assembly alignment pins in the upper internals of the Almarez and Dampierre PWRs. Photogrammetry is a three-dimensional precision measurement method using photographic techniques for the on-site measurement phase. On the strength of the operations at the two PWRs, underwater photogrammetry is now considered as a practical and effective technique for dimensional inspection at nuclear plants. (U.K.)

  15. Reactor pressure vessel steels

    International Nuclear Information System (INIS)

    Van De Velde, J.; Fabry, A.; Van Walle, E.; Chaouuadi, R.

    1998-01-01

    Research and development activities related to reactor pressure vessel steels during 1997 are reported. The objectives of activities of the Belgian Nuclear Research Centre SCK/CEN in this domain are: (1) to develop enhanced surveillance concepts by applying micromechanics and fracture-toughness tests to small specimens, and by performing damage modelling and microstructure characterization; (2) to demonstrate a methodology on a broad database; (3) to achieve regulatory acceptance and industrial use

  16. Hearing in the Juvenile Green Sea Turtle (Chelonia mydas: A Comparison of Underwater and Aerial Hearing Using Auditory Evoked Potentials.

    Directory of Open Access Journals (Sweden)

    Wendy E D Piniak

    Full Text Available Sea turtles spend much of their life in aquatic environments, but critical portions of their life cycle, such as nesting and hatching, occur in terrestrial environments, suggesting that it may be important for them to detect sounds in both air and water. In this study we compared underwater and aerial hearing sensitivities in five juvenile green sea turtles (Chelonia mydas by measuring auditory evoked potential responses to tone pip stimuli. Green sea turtles detected acoustic stimuli in both media, responding to underwater stimuli between 50 and 1600 Hz and aerial stimuli between 50 and 800 Hz, with maximum sensitivity between 200 and 400 Hz underwater and 300 and 400 Hz in air. When underwater and aerial hearing sensitivities were compared in terms of pressure, green sea turtle aerial sound pressure thresholds were lower than underwater thresholds, however they detected a wider range of frequencies underwater. When thresholds were compared in terms of sound intensity, green sea turtle sound intensity level thresholds were 2-39 dB lower underwater particularly at frequencies below 400 Hz. Acoustic stimuli may provide important environmental cues for sea turtles. Further research is needed to determine how sea turtles behaviorally and physiologically respond to sounds in their environment.

  17. Underwater welding and repair technologies applied in PWR environment

    International Nuclear Information System (INIS)

    Scandella, Fabrice; Carpreau, Jean-Michel

    2012-01-01

    The authors describe several welding processes and technologies which have been used for underwater applications and which can be applied when repairing components of a PWR type reactor. They address, describe and discuss wet arc welding processes, the peculiarities of underwater welding, and the use of various processes such as 111, 114 and 135 processes, underwater welding with the hybrid plasma MIG-MAG process, underwater welding with the laser wire process, underwater welding with the FSW, FSP or UWFSW processes, underwater welding with variants of the friction welding process (friction surfacing, taper stitch welding, hydro-pillar processing

  18. A noisy spring: the impact of globally rising underwater sound levels on fish.

    Science.gov (United States)

    Slabbekoorn, Hans; Bouton, Niels; van Opzeeland, Ilse; Coers, Aukje; ten Cate, Carel; Popper, Arthur N

    2010-07-01

    The underwater environment is filled with biotic and abiotic sounds, many of which can be important for the survival and reproduction of fish. Over the last century, human activities in and near the water have increasingly added artificial sounds to this environment. Very loud sounds of relatively short exposure, such as those produced during pile driving, can harm nearby fish. However, more moderate underwater noises of longer duration, such as those produced by vessels, could potentially impact much larger areas, and involve much larger numbers of fish. Here we call attention to the urgent need to study the role of sound in the lives of fish and to develop a better understanding of the ecological impact of anthropogenic noise. Copyright 2010 Elsevier Ltd. All rights reserved.

  19. Image processing algorithm for robot tracking in reactor vessel

    International Nuclear Information System (INIS)

    Kim, Tae Won; Choi, Young Soo; Lee, Sung Uk; Jeong, Kyung Min; Kim, Nam Kyun

    2011-01-01

    In this paper, we proposed an image processing algorithm to find the position of an underwater robot in the reactor vessel. Proposed algorithm is composed of Modified SURF(Speeded Up Robust Feature) based on Mean-Shift and CAMSHIFT(Continuously Adaptive Mean Shift Algorithm) based on color tracking algorithm. Noise filtering using luminosity blend method and color clipping are preprocessed. Initial tracking area for the CAMSHIFT is determined by using modified SURF. And then extracting the contour and corner points in the area of target tracked by CAMSHIFT method. Experiments are performed at the reactor vessel mockup and verified to use in the control of robot by visual tracking

  20. Human Injury Criteria for Underwater Blasts.

    Directory of Open Access Journals (Sweden)

    Rachel M Lance

    Full Text Available Underwater blasts propagate further and injure more readily than equivalent air blasts. Development of effective personal protection and countermeasures, however, requires knowledge of the currently unknown human tolerance to underwater blast. Current guidelines for prevention of underwater blast injury are not based on any organized injury risk assessment, human data or experimental data. The goal of this study was to derive injury risk assessments for underwater blast using well-characterized human underwater blast exposures in the open literature. The human injury dataset was compiled using 34 case reports on underwater blast exposure to 475 personnel, dating as early as 1916. Using severity ratings, computational reconstructions of the blasts, and survival information from a final set of 262 human exposures, injury risk models were developed for both injury severity and risk of fatality as functions of blast impulse and blast peak overpressure. Based on these human data, we found that the 50% risk of fatality from underwater blast occurred at 302±16 kPa-ms impulse. Conservatively, there is a 20% risk of pulmonary injury at a kilometer from a 20 kg charge. From a clinical point of view, this new injury risk model emphasizes the large distances possible for potential pulmonary and gut injuries in water compared with air. This risk value is the first impulse-based fatality risk calculated from human data. The large-scale inconsistency between the blast exposures in the case reports and the guidelines available in the literature prior to this study further underscored the need for this new guideline derived from the unique dataset of actual injuries in this study.

  1. The Modular Optical Underwater Survey System

    Directory of Open Access Journals (Sweden)

    Ruhul Amin

    2017-10-01

    Full Text Available The Pacific Islands Fisheries Science Center deploys the Modular Optical Underwater Survey System (MOUSS to estimate the species-specific, size-structured abundance of commercially-important fish species in Hawaii and the Pacific Islands. The MOUSS is an autonomous stereo-video camera system designed for the in situ visual sampling of fish assemblages. This system is rated to 500 m and its low-light, stereo-video cameras enable identification, counting, and sizing of individuals at a range of 0.5–10 m. The modular nature of MOUSS allows for the efficient and cost-effective use of various imaging sensors, power systems, and deployment platforms. The MOUSS is in use for surveys in Hawaii, the Gulf of Mexico, and Southern California. In Hawaiian waters, the system can effectively identify individuals to a depth of 250 m using only ambient light. In this paper, we describe the MOUSS’s application in fisheries research, including the design, calibration, analysis techniques, and deployment mechanism.

  2. The effect of explosive percentage on underwater explosion energy release of hexanitrohexaazaisowurtzitane and octogen based aluminized explosives

    OpenAIRE

    Qingjie Jiao; Qiushi Wang; Jianxin Nie; Xueyong Guo; Wei Zhang; Wenqi Fan

    2018-01-01

    To control the explosion energy output by optimizing explosive components is a key requirement in a number of different application areas. The effect of different Al/O Ratio on underwater explosion of aluminized explosives has been studied detailedly. However, the effect of explosive percentage in the same Al/O Ratio is rarely researched, especially for Hexanitrohexaazaisowurtzitane (CL-20) based aluminized explosives. In this study, we performed the underwater explosion experiments with 1.2-...

  3. State of opening the cover and carrying out the checkup of the reactor vessel of the nuclear-powered ship 'Mutsu' by Japan Atomic Energy Research Institute

    International Nuclear Information System (INIS)

    1989-01-01

    In the checkup by opening the cover of the reactor vessel of the nuclear-powered ship 'Mutsu', Japan Atomic Energy Research Institute carried out the checkup and maintenance for the reactor proper, control system and primary coolant facilities including the secondary side of steam generators and the pressure balancing valve of the containment vessel. The works were classified into the opening of the reactor, checkup, maintenance and restoration. The opening was begun on August 4, 1988, and finished on December 5. The checkup and maintenance were begun on September 22, and are still continued now. The maximum radiation dose rate on the surfaces of fuel assemblies and control rods and at the positions 1 m distant from them was measured. The results of the checkup of various components are reported. In 290 absorbent rods of control rods, spot corrosion and discoloration were observed, of which the spot corrosion penetrated the walls of 4 rods. Also in 12 fuel rods, spot corrosion was observed near the welded end plugs, but leak was not observed. (K.I.)

  4. Expanded Fermilab pressure vessel directory program

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, A.

    1983-01-01

    Several procedures have been written to manage the information pertaining to the vacuum tanks and pressure vessels for which the laboratory is responsible. These procedures have been named TANK1 for the vessels belonging to the Accelerator Division, TANK2 and TANK3 for the vessels belonging to the Research Division and to Technical Support respectively, and TANK4 for the vessels belonging to the Business Division. The operating procedures are otherwise identical in every respect.

  5. Expanded Fermilab pressure vessel directory program

    International Nuclear Information System (INIS)

    Tanner, A.

    1983-01-01

    Several procedures have been written to manage the information pertaining to the vacuum tanks and pressure vessels for which the laboratory is responsible. These procedures have been named TANK1 for the vessels belonging to the Accelerator Division, TANK2 and TANK3 for the vessels belonging to the Research Division and to Technical Support respectively, and TANK4 for the vessels belonging to the Business Division. The operating procedures are otherwise identical in every respect

  6. Optimal Node Placement in Underwater Wireless Sensor Networks

    KAUST Repository

    Felamban, M.; Shihada, Basem; Jamshaid, K.

    2013-01-01

    Wireless Sensor Networks (WSN) are expected to play a vital role in the exploration and monitoring of underwater areas which are not easily reachable by humans. However, underwater communication via acoustic waves is subject to several performance

  7. Underwater Sensor Networks: A New Energy Efficient and Robust Architecture

    NARCIS (Netherlands)

    Climent, Salvador; Capella, Juan Vincente; Meratnia, Nirvana; Serrano, Juan José

    2012-01-01

    The specific characteristics of underwater environments introduce new challenges for networking protocols. In this paper, a specialized architecture for underwater sensor networks (UWSNs) is proposed and evaluated. Experiments are conducted in order to analyze the suitability of this protocol for

  8. Underwater Calibration of Dome Port Pressure Housings

    Science.gov (United States)

    Nocerino, E.; Menna, F.; Fassi, F.; Remondino, F.

    2016-03-01

    Underwater photogrammetry using consumer grade photographic equipment can be feasible for different applications, e.g. archaeology, biology, industrial inspections, etc. The use of a camera underwater can be very different from its terrestrial use due to the optical phenomena involved. The presence of the water and camera pressure housing in front of the camera act as additional optical elements. Spherical dome ports are difficult to manufacture and consequently expensive but at the same time they are the most useful for underwater photogrammetry as they keep the main geometric characteristics of the lens unchanged. Nevertheless, the manufacturing and alignment of dome port pressure housing components can be the source of unexpected changes of radial and decentring distortion, source of systematic errors that can influence the final 3D measurements. The paper provides a brief introduction of underwater optical phenomena involved in underwater photography, then presents the main differences between flat and dome ports to finally discuss the effect of manufacturing on 3D measurements in two case studies.

  9. Nonuniform Illumination Correction Algorithm for Underwater Images Using Maximum Likelihood Estimation Method

    Directory of Open Access Journals (Sweden)

    Sonali Sachin Sankpal

    2016-01-01

    Full Text Available Scattering and absorption of light is main reason for limited visibility in water. The suspended particles and dissolved chemical compounds in water are also responsible for scattering and absorption of light in water. The limited visibility in water results in degradation of underwater images. The visibility can be increased by using artificial light source in underwater imaging system. But the artificial light illuminates the scene in a nonuniform fashion. It produces bright spot at the center with the dark region at surroundings. In some cases imaging system itself creates dark region in the image by producing shadow on the objects. The problem of nonuniform illumination is neglected by the researchers in most of the image enhancement techniques of underwater images. Also very few methods are discussed showing the results on color images. This paper suggests a method for nonuniform illumination correction for underwater images. The method assumes that natural underwater images are Rayleigh distributed. This paper used maximum likelihood estimation of scale parameter to map distribution of image to Rayleigh distribution. The method is compared with traditional methods for nonuniform illumination correction using no-reference image quality metrics like average luminance, average information entropy, normalized neighborhood function, average contrast, and comprehensive assessment function.

  10. Will an underwater robot ever replace the diver? A rather poor progress or a great success?

    Directory of Open Access Journals (Sweden)

    Olejnik Adam

    2016-03-01

    Full Text Available The article deals with the subject matter related to the development of underwater works technologies. Nearly 15 years ago one of the authors of this study published a material in the monthly magazine of “Podwodny Świat” (The Underwater World entitled “The Future of Underwater Technologies – the diver or the robot?” where he noted that the time of great changes in technologies aimed at researching the depths and conducting works under water has arrived. This new era mainly consists in the fact that on an increasing number of occasions the diver is replaced by an underwater robot. The presented material constitutes an attempt to provide an answer to the question whether the then posed thesis is still valid. In the article the authors discuss issues concerned with the development of techniques and technologies applied in the conquest of depths that leads them to the conclusion that the previously observed tendency of a double-tracked development of underwater technologies is gaining in strength, which causes that the works and exploration of bodies of water at great depths will be possible only with the use of unmanned techniques.

  11. CFD Based Added Mass Prediction in Cruise Condition of Underwater Vehicle Dynamic

    Science.gov (United States)

    Agoes Moelyadi, Mochammad; Bambang Riswandi, Bagus

    2018-04-01

    One of the unsteady flow behavior on the hydrodynamic characteristics of underwater vehicle is the presence of added mass. In cruising conditions, the underwater vehicle may require the addition of speed or experience the disturbance in the form of unsteady flow so that cause the hydrodynamic interaction between the surface of the vehicle with the surrounding fluid. This leads to the rise of local velocity of flow and the great changes of hydrodynamic forces which are very influential on the stability of the underwater vehicle. One of the result is an additional force called added mass. It is very useful parameter to control underwater vehicle dynamic.This paper reports the research on the added mass coefficient of underwater vehicles obtained through the Computational Fluid Dynmaic (CFD) simulation method using CFX software. Added mass coefficient is calculated by performing an unsteady simulation or known as transient simulation. Computational simulations are based on the Reynold Average Navier- Stokes (RANS) equation solution. The simulated vehicle moves forward and backward according to the sinus function, with a frequency of 0.25 Hz, a 2 m amplitude, a cruising depth of 10 m below sea level, and Vcruise 1.54 m / s (Re = 9.000.000). Simulation result data includes velocity contour, variation of force and acceleration to frequency, and added mass coefficient.

  12. Centralised versus Decentralised Control Reconfiguration for Collaborating Underwater Robots

    DEFF Research Database (Denmark)

    Furno, Lidia; Nielsen, Mikkel Cornelius; Blanke, Mogens

    2015-01-01

    The present paper introduces an approach to fault-tolerant reconfiguration for collaborating underwater robots. Fault-tolerant reconfiguration is obtained using the virtual actuator approach, Steen (2005). The paper investigates properties of a centralised versus a decentralised implementation an...... an underwater drill needs to be transported and positioned by three collaborating robots as part of an underwater autonomous operation....

  13. R.M.S Titanic 2003 Expedition on the Russian Research Vessel Akademik Mstislav Keldysh between 20030622 and 20030702

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As the leading ocean agency, and as per the Guidelines for Research, Exploration and Salvage of RMS Titanic, issued under the authority of the RMS Titanic Maritime...

  14. The importance of Forensic research in the Nuclear Power Industry. What the OECD Three Mile Island reactor vessel investigation. Means to the future of commercial nuclear power

    International Nuclear Information System (INIS)

    Rogers, K.C.

    1994-01-01

    TMI-2 altered the perception of the likelihood of severe accidents and their precursors and shortly after the accident, changes began at the NRC. NRC required its nuclear power licensees to make a rather large number of back fits to respond to the lessons learned; NRC broadened the study of severe accident phenomena (focus on studies involving molten core materials); other lessons learned concerned the severe accident source terms and the shift from a deterministic tradition point of view to a probabilistic risk assessment formalism. A Revised Severe Accident Research Program Plan was issued in 1989. A review of what was known before the TMI-Vessel Investigation Project and what was not known, is presented

  15. Vessel Operator System

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Operator cards are required for any operator of a charter/party boat and or a commercial vessel (including carrier and processor vessels) issued a vessel permit from...

  16. Application of underwater radon measurements in geology

    Energy Technology Data Exchange (ETDEWEB)

    Varhegyi, A.; Baranyi, I.; Gerzson, I. (Mecsek Ore Mining Enterprise, Pecs (Hungary)); Somogyi, G.; Hakl, J.; Hunyadi, I. (Magyar Tudomanyos Akademia, Debrecen (Hungary). Atommag Kutato Intezete)

    1988-01-01

    Based on the observed phenomenon of geogas migration in microbubble form from deeper regions, the authors have developed a new model for the vertical transport of radon released from deeper sources. The physical properties of the rock relating to the upflow of microbubbles below the groundwater level are considered and the radon transport parameter of rocks is introduced. The vertical distribution of radon concentration in the case of a multi-layered geological model is given and the penetration depth of underwater radon measurements is examined. Aspects of underwater radon detection by the nuclear track detector technique are analyzed. The radon transport model gives a new theoretical basis for several applications of radon measurements in geology. The advantages of underwater radon detection have already been proved in uranium exploration. Further geological applications are proposed in earthquake prediction, in volcanology, in the survey of active faults and thermal waters. (author).

  17. Monitoring Coral Growth - the Dichotomy Between Underwater Photogrammetry and Geodetic Control Network

    Science.gov (United States)

    Neyer, F.; Nocerino, E.; Gruen, A.

    2018-05-01

    Creating 3-dimensional (3D) models of underwater scenes has become a common approach for monitoring coral reef changes and its structural complexity. Also in underwater archeology, 3D models are often created using underwater optical imagery. In this paper, we focus on the aspect of detecting small changes in the coral reef using a multi-temporal photogrammetric modelling approach, which requires a high quality control network. We show that the quality of a good geodetic network limits the direct change detection, i.e., without any further registration process. As the photogrammetric accuracy is expected to exceed the geodetic network accuracy by at least one order of magnitude, we suggest to do a fine registration based on a number of signalized points. This work is part of the Moorea Island Digital Ecosystem Avatar (IDEA) project that has been initiated in 2013 by a group of international researchers (https://mooreaidea.ethz.ch/).

  18. The key kinematic determinants of undulatory underwater swimming at maximal velocity.

    Science.gov (United States)

    Connaboy, Chris; Naemi, Roozbeh; Brown, Susan; Psycharakis, Stelios; McCabe, Carla; Coleman, Simon; Sanders, Ross

    2016-01-01

    The optimisation of undulatory underwater swimming is highly important in competitive swimming performance. Nineteen kinematic variables were identified from previous research undertaken to assess undulatory underwater swimming performance. The purpose of the present study was to determine which kinematic variables were key to the production of maximal undulatory underwater swimming velocity. Kinematic data at maximal undulatory underwater swimming velocity were collected from 17 skilled swimmers. A series of separate backward-elimination analysis of covariance models was produced with cycle frequency and cycle length as dependent variables (DVs) and participant as a fixed factor, as including cycle frequency and cycle length would explain 100% of the maximal swimming velocity variance. The covariates identified in the cycle-frequency and cycle-length models were used to form the saturated model for maximal swimming velocity. The final parsimonious model identified three covariates (maximal knee joint angular velocity, maximal ankle angular velocity and knee range of movement) as determinants of the variance in maximal swimming velocity (adjusted-r2 = 0.929). However, when participant was removed as a fixed factor there was a large reduction in explained variance (adjusted r2 = 0.397) and only maximal knee joint angular velocity continued to contribute significantly, highlighting its importance to the production of maximal swimming velocity. The reduction in explained variance suggests an emphasis on inter-individual differences in undulatory underwater swimming technique and/or anthropometry. Future research should examine the efficacy of other anthropometric, kinematic and coordination variables to better understand the production of maximal swimming velocity and consider the importance of individual undulatory underwater swimming techniques when interpreting the data.

  19. Benchmark Analyses of Sodium Natural Convection in the Upper Plenum of the Monju Reactor Vessel. Final Report of a Coordinated Research Project 2008-2012

    International Nuclear Information System (INIS)

    2014-11-01

    The IAEA supports Member States in the area of advanced fast reactor technology development by providing a major fulcrum for information exchange and collaborative research programmes. The IAEA’s activities in this field are mainly carried out within the framework of the Technical Working Group on Fast Reactors (TWG-FR), which assists in the implementation of corresponding IAEA support, and ensures that all technical activities are in line with expressed needs of Member States. Among this broad range, the IAEA proposes and establishes coordinated research projects (CRPs), aimed at improving Member State capability in fast reactor design and analysis. An important opportunity to perform collaborative research activities was provided by the system startup tests carried out by the Japan Atomic Energy Agency (JAEA) in the prototype loop type sodium cooled fast reactor Monju, in particular a turbine trip test performed in December 1995. As the JAEA opened the experimental dataset to international collaboration in 2008, the IAEA launched the CRP on Benchmark Analyses of Sodium Natural Convection in the Upper Plenum of the Monju Reactor Vessel. The CRP, together with eight institutes from seven States, has contributed to improving capabilities in sodium cooled fast reactors simulation through code verification and validation, with particular emphasis on thermal stratification and natural circulation phenomena

  20. Underwater Acoustic Wireless Sensor Networks: Advances and Future Trends in Physical, MAC and Routing Layers

    NARCIS (Netherlands)

    Climent, S.; Sanchez, A.; Capella, J.V.; Meratnia, Nirvana; Serrano, J.J.

    2014-01-01

    This survey aims to provide a comprehensive overview of the current research on underwater wireless sensor networks, focusing on the lower layers of the communication stack, and envisions future trends and challenges. It analyzes the current state-of-the-art on the physical, medium access control

  1. Human Factors Issues When Operating Underwater Remotely Operated Vehicles and Autonomous Underwater Vehicles

    Science.gov (United States)

    2011-03-01

    etiquette (Parasuraman & Miller, 2004). Through natural and intuitive communication, Johnson et al., (2007) hope that this interface will instill greater...and etiquette in high criticality automated systems. Communications of the ACM, 47(4), 51-55. Parasuraman, R., & Riley, V. (1997). Humans and... protocols for underwater wireless communications. IEEE Communications Magazine, pp. 97-102. Quazi, A. H., & Konrad, W. L. (1982, March 1982). Underwater

  2. IVO develops a new repair technique for underwater sites. Viscous doughlike substance underwater cracks

    Energy Technology Data Exchange (ETDEWEB)

    Klingstedt, G.; Leisio, C. [ed.

    1998-07-01

    A viscous sealant is revolutionizing repair of the stone and concrete masonry of underwater dams, bridges and canals. There is now no need for expensive and time-consuming cofferdams, since a diver can extrude quick-setting mortar into underwater structures needing repair. This technique has worked well in recent years in various parts of Finland even in strongly flowing water. IVO experts are now starting to look more beyond the borders of Finland

  3. Investigation on dissimilar underwater friction stir lap welding of 6061-T6 aluminum alloy to pure copper

    International Nuclear Information System (INIS)

    Zhang, Jingqing; Shen, Yifu; Yao, Xin; Xu, Haisheng; Li, Bo

    2014-01-01

    Highlights: • 6061-T6 Al and pure Cu were successfully underwater friction stir lap welded. • The underwater weld was analyzed via comparing with the classical weld. • The oxidation of Cu was prevented via the external water. • The amount of Al–Cu intermetallic was decreased by the external water. • The thickness of Al–Cu diffusion interlayer was decreased by the external water. - Abstract: Friction stir welding (classical FSW) is considered to offer advantages over the traditional fusion welding techniques in terms of dissimilar welding. However, some challenges still exist in the dissimilar friction stir lap welding of the aluminum/copper (Al/Cu) metallic couple, among which the formation of the Al–Cu intermetallic compounds is the major problem. In the present research, due to the fact that the formation and growth of the intermetallic are significantly controlled by the thermal history, the underwater friction stir welding (underwater FSW) was employed for fabricating the weld, and the weld obtained by underwater FSW (underwater weld) was analyzed via comparing with the weld obtained under same parameters by classical FSW (classical weld). In order to investigate the effect of the external water on the thermal history, the K-type thermocouple was utilized to measure the weld temperature, and it is found that the water could decrease the peak temperature and shorten the thermal cycle time. The XRD results illustrate that the interface of the welds mainly consist of the Al–Cu intermetallic compounds such as CuAl 2 and Cu 9 Al 4 together with some amounts of Al and Cu, and it is also found that the amount of the intermetallic in the underwater weld is obvious less than in the classical weld. The SEM images and the EDS line scan results also illustrate that the Al–Cu diffusion interlayer at the Al–Cu interface of the underwater weld was obviously thinner than that of the classical weld

  4. Examination of VVER-1000 Reactor Pressure Vessel

    International Nuclear Information System (INIS)

    Matokovic, A.; Picek, E.; Markulin, K.

    2008-01-01

    The increasing demand of a higher level of safety in the operation of the nuclear power plants requires the utilisation of more precise automated equipment to perform in-service inspections. That has been achieved by technological advances in computer technology, in robotics, in examination probe technology with the development of the advanced inspection technique and has also been due to the considerable and varied experience gained in the performance of such inspections. In-service inspection of reactor pressure vessel, especially Russian-designed WWER-1000 presents one of the most important and extensive examination of nuclear power plants primary circuit components. Such examination demand high standards of inspection technology, quality and continual innovation in the field of non-destructive testing advanced technology. A remote underwater contact ultrasonic technique is employed for the examination of the base metal of vessel and reactor welds, whence eddy current method is applied for clad surface examinations. Visual testing is used for examination of the vessel interior. The movement of inspection probes and data positioning are assured by using new reactor pressure vessel tool concept that is fully integrated with inspection systems. The successful performance of reactor pressure vessel is attributed thorough pre-outage planning, training and successful performance demonstration qualification of chosen non-destructive techniques on the specimens with artificial and/or real defects. Furthermore, use of advanced approach of inspection through implementation the state-of-the-art examination equipment significantly reduced the inspection time, radiation exposure to examination personnel, shortening nuclear power plant outage and cutting the total inspection costs. This paper presents advanced approach in the reactor pressure vessel in-service inspections and it is especially developed for WWER-1000 nuclear power plants.(author)

  5. Research and development of spent-fuel shipping casks and the criteria for sea-going vessels carrying them

    International Nuclear Information System (INIS)

    Aoki, S.; Ando, Y.

    1977-01-01

    Since the transport of spent fuel will increase rapidly and extensively in the near future, the Japanese Atomic Energy Committee enacted the Technical Standard for Transportation of Radioactive Materials, based on the IAEA Regulation for the Safe Transport of Radioactive Materials, 1973 Revised Edition. The authorities concerned have begun to review the former ordinances for transporting radioactive materials and to develop a unified system of relevant laws and standards. For ten years the Atomic Energy Bureau has invested in research and development to obtain data for the design and licence of a spent-fuel shipping cask. Different scale models of a prototype weighing 80t were used to clarify the scale effect of drop, puncture and fire tests, which are a feature of Japanese research and development. Also an immersion test in water at pressures up to about 500 bar is now carried out to investigate the integrity of the cask body and sealing structure to prevent leakage of radioactive contents to the surroundings should the cask fall into deep sea. In Japan, depending on the site of nuclear plants, almost all transport of unirradiated and spent fuels is by sea. Therefore, to secure safe transport, the design criteria of ships for the exclusive transport of spent-fuel shipping casks, namely full-load shipping, have been enacted, which aim to make the likelihood of sinking on collision, stranding, and other unforeseen accidents at sea highly improbable and also to keep radiation exposure of the crew as low as possible. (author)

  6. The Control Packet Collision Avoidance Algorithm for the Underwater Multichannel MAC Protocols via Time-Frequency Masking

    Directory of Open Access Journals (Sweden)

    Yang Yu

    2016-01-01

    Full Text Available Establishing high-speed and reliable underwater acoustic networks among multiunmanned underwater vehicles (UUVs is basic to realize cooperative and intelligent control among different UUVs. Nevertheless, different from terrestrial network, the propagation speed of the underwater acoustic network is 1500 m/s, which makes the design of the underwater acoustic network MAC protocols a big challenge. In accordance with multichannel MAC protocols, data packets and control packets are transferred through different channels, which lowers the adverse effect of acoustic network and gradually becomes the popular issues of underwater acoustic networks MAC protocol research. In this paper, we proposed a control packet collision avoidance algorithm utilizing time-frequency masking to deal with the control packets collision in the control channel. This algorithm is based on the scarcity of the noncoherent underwater acoustic communication signals, which regards collision avoiding as separation of the mixtures of communication signals from different nodes. We first measure the W-Disjoint Orthogonality of the MFSK signals and the simulation result demonstrates that there exists time-frequency mask which can separate the source signals from the mixture of the communication signals. Then we present a pairwise hydrophones separation system based on deep networks and the location information of the nodes. Consequently, the time-frequency mask can be estimated.

  7. Underwater noise generated by offshore pile driving

    NARCIS (Netherlands)

    Tsouvalas, A.

    2015-01-01

    Anthropogenic noise emission in the marine environment has always been an environmental issue of serious concern. In particular, the noise generated during the installation of foundation piles is considered to be one of the most significant sources of underwater noise pollution. This is mainly

  8. Underwater image mosaicking and visual odometry

    Science.gov (United States)

    Sadjadi, Firooz; Tangirala, Sekhar; Sorber, Scott

    2017-05-01

    This paper summarizes the results of studies in underwater odometery using a video camera for estimating the velocity of an unmanned underwater vehicle (UUV). Underwater vehicles are usually equipped with sonar and Inertial Measurement Unit (IMU) - an integrated sensor package that combines multiple accelerometers and gyros to produce a three dimensional measurement of both specific force and angular rate with respect to an inertial reference frame for navigation. In this study, we investigate the use of odometry information obtainable from a video camera mounted on a UUV to extract vehicle velocity relative to the ocean floor. A key challenge with this process is the seemingly bland (i.e. featureless) nature of video data obtained underwater which could make conventional approaches to image-based motion estimation difficult. To address this problem, we perform image enhancement, followed by frame to frame image transformation, registration and mosaicking/stitching. With this approach the velocity components associated with the moving sensor (vehicle) are readily obtained from (i) the components of the transform matrix at each frame; (ii) information about the height of the vehicle above the seabed; and (iii) the sensor resolution. Preliminary results are presented.

  9. Efficient Modelling Methodology for Reconfigurable Underwater Robots

    DEFF Research Database (Denmark)

    Nielsen, Mikkel Cornelius; Blanke, Mogens; Schjølberg, Ingrid

    2016-01-01

    This paper considers the challenge of applying reconfigurable robots in an underwater environment. The main result presented is the development of a model for a system comprised of N, possibly heterogeneous, robots dynamically connected to each other and moving with 6 Degrees of Freedom (DOF). Th...

  10. Underwater Adhesives Retrofit Pipelines with Advanced Sensors

    Science.gov (United States)

    2015-01-01

    Houston-based Astro Technology Inc. used a partnership with Johnson Space Center to pioneer an advanced fiber-optic monitoring system for offshore oil pipelines. The company's underwater adhesives allow it to retrofit older deepwater systems in order to measure pressure, temperature, strain, and flow properties, giving energy companies crucial data in real time and significantly decreasing the risk of a catastrophe.

  11. Human Injury Criteria for Underwater Blasts

    Science.gov (United States)

    2014-09-08

    further underscored the need for this new guideline based on injury data. Conference Name: Personal Armour Systems Symposium Conference Date...29.  Cole, R., Underwater Explosion. (Dover Publications, Inc ., New York, N.Y., 1948) 30.  Nakahara, M., Nagayama, K, Mori, Y, Japanese Journal...Abstract of the Undersea and Hyperbaric Medical Society, Inc . Annual Scientific Meeting, (1976).

  12. Gammatography of thick lead vessels

    International Nuclear Information System (INIS)

    Raghunath, V.M.; Bhatnagar, P.K.; Sundaram, V.M.

    1979-01-01

    Radiography, scintillation and GM counting and dose measurements using ionisation chamber equipment are commonly used for detecting flaws/voids in materials. The first method is mostly used for steel vessels and to a lesser extent thin lead vessels also and is essentially qualitative. Dose measuring techniques are used for very thick and large lead vessels for which high strength radioactive sources are required, with its inherent handling problems. For vessels of intermediate thicknesses, it is ideal to use a small strength source and a GM or scintillation counter assembly. At the Reactor Research Centre, Kalpakkam, such a system was used for checking three lead vessels of thicknesses varying from 38mm to 65mm. The tolerances specified were +- 4% variation in lead thickness. The measurements also revealed the non concentricity of one vessel which had a thickness varying from 38mm to 44mm. The second vessel was patently non-concentric and the dimensional variation was truly reproduced in the measurements. A third vessel was fabricated with careful control of dimensions and the measurements exhibited good concentricity. Small deviations were observed, attributable to imperfect bondings between steel and lead. This technique has the following advantages: (a) weaker sources used result in less handling problems reducing the personnel exposures considerably; (b) the sensitivity of the instrument is quite good because of better statistics; (c) the time required for scanning a small vessel is more, but a judicious use of a scintillometer for initial fast scan will help in reducing the total scanning time; (d) this method can take advantage of the dimensional variations themselves to get the calibration and to estimate the deviations from specified tolerances. (auth.)

  13. Communication and cooperation in underwater acoustic networks

    Science.gov (United States)

    Yerramalli, Srinivas

    In this thesis, we present a study of several problems related to underwater point to point communications and network formation. We explore techniques to improve the achievable data rate on a point to point link using better physical layer techniques and then study sensor cooperation which improves the throughput and reliability in an underwater network. Robust point-to-point communications in underwater networks has become increasingly critical in several military and civilian applications related to underwater communications. We present several physical layer signaling and detection techniques tailored to the underwater channel model to improve the reliability of data detection. First, a simplified underwater channel model in which the time scale distortion on each path is assumed to be the same (single scale channel model in contrast to a more general multi scale model). A novel technique, which exploits the nature of OFDM signaling and the time scale distortion, called Partial FFT Demodulation is derived. It is observed that this new technique has some unique interference suppression properties and performs better than traditional equalizers in several scenarios of interest. Next, we consider the multi scale model for the underwater channel and assume that single scale processing is performed at the receiver. We then derive optimized front end pre-processing techniques to reduce the interference caused during single scale processing of signals transmitted on a multi-scale channel. We then propose an improvised channel estimation technique using dictionary optimization methods for compressive sensing and show that significant performance gains can be obtained using this technique. In the next part of this thesis, we consider the problem of sensor node cooperation among rational nodes whose objective is to improve their individual data rates. We first consider the problem of transmitter cooperation in a multiple access channel and investigate the stability of

  14. Underwater Photosynthesis of Submerged Plants – Recent Advances and Methods

    Science.gov (United States)

    Pedersen, Ole; Colmer, Timothy D.; Sand-Jensen, Kaj

    2013-01-01

    We describe the general background and the recent advances in research on underwater photosynthesis of leaf segments, whole communities, and plant dominated aquatic ecosystems and present contemporary methods tailor made to quantify photosynthesis and carbon fixation under water. The majority of studies of aquatic photosynthesis have been carried out with detached leaves or thalli and this selectiveness influences the perception of the regulation of aquatic photosynthesis. We thus recommend assessing the influence of inorganic carbon and temperature on natural aquatic communities of variable density in addition to studying detached leaves in the scenarios of rising CO2 and temperature. Moreover, a growing number of researchers are interested in tolerance of terrestrial plants during flooding as torrential rains sometimes result in overland floods that inundate terrestrial plants. We propose to undertake studies to elucidate the importance of leaf acclimation of terrestrial plants to facilitate gas exchange and light utilization under water as these acclimations influence underwater photosynthesis as well as internal aeration of plant tissues during submergence. PMID:23734154

  15. Research on friction coefficient of nuclear Reactor Vessel Internals Hold Down Spring: Stress coefficient test analysis method

    International Nuclear Information System (INIS)

    Linjun, Xie; Guohong, Xue; Ming, Zhang

    2016-01-01

    Graphical abstract: HDS stress coefficient test apparatus. - Highlights: • This paper performs mathematic deduction to the physical model of Hold Down Spring (HDS), establishes a mathematic model of axial load P and stress, stress coefficient and friction coefficient and designs a set of test apparatuses for simulating the pretightening process of the HDS for the first time according to a model similarity criterion. • The mathematical relation between the load and the strain is obtained about the HDS, and the mathematical model of the stress coefficient and the friction coefficient is established. So, a set of test apparatuses for obtaining the stress coefficient is designed according to the model scaling criterion and the friction coefficient of the K1000 HDS is calculated to be 0.336 through the obtained stress coefficient. • The relation curve between the theoretical load and the friction coefficient is obtained through analysis and indicates that the change of the friction coefficient f would influence the pretightening load under the condition of designed stress. The necessary pretightening load in the design process is calculated to be 5469 kN according to the obtained friction coefficient. Therefore, the friction coefficient and the pretightening load under the design conditions can provide accurate pretightening data for the analysis and design of the reactor HDS according to the operations. - Abstract: This paper performs mathematic deduction to the physical model of Hold Down Spring (HDS), establishes a mathematic model of axial load P and stress, stress coefficient and friction coefficient and designs a set of test apparatuses for simulating the pretightening process of the HDS for the first time according to a model similarity criterion. By carrying out tests and researches through a stress testing technique, P–σ curves in loading and unloading processes of the HDS are obtained and the stress coefficient k f of the HDS is obtained. So, the

  16. Research on friction coefficient of nuclear Reactor Vessel Internals Hold Down Spring: Stress coefficient test analysis method

    Energy Technology Data Exchange (ETDEWEB)

    Linjun, Xie, E-mail: linjunx@zjut.edu.cn [College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Guohong, Xue; Ming, Zhang [Shanghai Nuclear Engineering Research & Design Institute, Shanghai 200233 (China)

    2016-08-01

    Graphical abstract: HDS stress coefficient test apparatus. - Highlights: • This paper performs mathematic deduction to the physical model of Hold Down Spring (HDS), establishes a mathematic model of axial load P and stress, stress coefficient and friction coefficient and designs a set of test apparatuses for simulating the pretightening process of the HDS for the first time according to a model similarity criterion. • The mathematical relation between the load and the strain is obtained about the HDS, and the mathematical model of the stress coefficient and the friction coefficient is established. So, a set of test apparatuses for obtaining the stress coefficient is designed according to the model scaling criterion and the friction coefficient of the K1000 HDS is calculated to be 0.336 through the obtained stress coefficient. • The relation curve between the theoretical load and the friction coefficient is obtained through analysis and indicates that the change of the friction coefficient f would influence the pretightening load under the condition of designed stress. The necessary pretightening load in the design process is calculated to be 5469 kN according to the obtained friction coefficient. Therefore, the friction coefficient and the pretightening load under the design conditions can provide accurate pretightening data for the analysis and design of the reactor HDS according to the operations. - Abstract: This paper performs mathematic deduction to the physical model of Hold Down Spring (HDS), establishes a mathematic model of axial load P and stress, stress coefficient and friction coefficient and designs a set of test apparatuses for simulating the pretightening process of the HDS for the first time according to a model similarity criterion. By carrying out tests and researches through a stress testing technique, P–σ curves in loading and unloading processes of the HDS are obtained and the stress coefficient k{sub f} of the HDS is obtained. So, the

  17. Immunological quality and performance of tumor vessel-targeting CAR-T cells prepared by mRNA-EP for clinical research.

    Science.gov (United States)

    Inoo, Kanako; Inagaki, Ryo; Fujiwara, Kento; Sasawatari, Shigemi; Kamigaki, Takashi; Nakagawa, Shinsaku; Okada, Naoki

    2016-01-01

    We previously reported that tumor vessel-redirected T cells, which were genetically engineered with chimeric antigen receptor (CAR) specific for vascular endothelial growth factor receptor 2 (VEGFR2), demonstrated significant antitumor effects in various murine solid tumor models. In the present study, we prepared anti-VEGFR2 CAR-T cells by CAR-coding mRNA electroporation (mRNA-EP) and analyzed their immunological characteristics and functions for use in clinical research. The expression of anti-VEGFR2 CAR on murine and human T cells was detected with approximately 100% efficiency for a few days, after peaking 6-12 hours after mRNA-EP. Triple transfer of murine anti-VEGFR2 CAR-T cells into B16BL6 tumor-bearing mice demonstrated an antitumor effect comparable to that for the single transfer of CAR-T cells engineered with retroviral vector. The mRNA-EP did not cause any damage or defects to human T-cell characteristics, as determined by viability, growth, and phenotypic parameters. Additionally, two kinds of human anti-VEGFR2 CAR-T cells, which expressed different CAR construction, differentiated to effector phase with cytokine secretion and cytotoxic activity in antigen-specific manner. These results indicate that our anti-VEGFR2 CAR-T cells prepared by mRNA-EP have the potential in terms of quality and performance to offer the prospect of safety and efficacy in clinical research as cellular medicine.

  18. Natural hydrocarbon seeps observation with underwater gliders and UV fluorescence sensor

    Science.gov (United States)

    Rochet, V.

    2016-02-01

    Hydrocarbons may leak to the near-surface from subsurface accumulations, from mature source rock, or by buoyancy along major cross-strata routes. The presence of migrating near-surface hydrocarbons can provide strong evidence for the presence of a working petroleum system, as well as valuable information on source, maturity, and migration pathways. Detection and characterization of hydrocarbons in the water column may then help to de-risk hydrocarbon plays at a very preliminary stage of an exploration program. In order to detect hydrocarbons in the water column, an underwater glider survey was conducted in an offshore frontier area. Driven by buoyancy variation, underwater gliders enable collecting data autonomously along the water column for weeks to months. Underwater gliders are regularly piloted from shore by satellite telemetry and do not require a surface supervising vessel resulting in substantial operational costs savings. The data compiled, over 700m depth of the water column, included temperature, salinity, pressure, dissolved oxygen and hydrocarbon components (phenanthrene and naphthalene) measured by "MINIFLUO" sensors to particularly target representative crude oil compounds Two gliders were deployed at sea, one from coast in shallow water and the other one offshore on the survey area. Both accurately squared the survey area following pre-defined lines and cross lines. Data files were transmitted by satellite telemetry in near real time during the performance of the mission for real time observations and appropriate re-positioning of the gliders. Using rechargeable underwater gliders increased reliability reducing the risk of leakage and associated logistics during operation at sea. Despite strong evidences of seabed seepages such as pockmarks, faults, etc, over the area of interest, no hydrocarbon indices were detected in the water column, which was confirmed later by seabed sample analysis. The use of glider platforms for hydrocarbon detection has

  19. Erratum: Google Earth as Geoscience Data Browser Project: Development of a Tool to Convert JAMSTEC Research Vessel Navigation Data to KML [Data Science Journal, Volume 8, 30 March 2009. S85-S91

    Directory of Open Access Journals (Sweden)

    Y Yamagishi

    2009-07-01

    Full Text Available The following PDF indicates errata for the original article entitled "Google Earth as Geoscience Data Browser Project: Development of a Tool to Convert JAMSTEC Research Vessel Navigation Data to KML" by Y Yamagishi, H Nagao, K Suzuki, H Tamura, T Hatakeyama, H Yanaka and S Tsuboi.

  20. LopheliaII2012: Coral Research on Oil Rigs in the Gulf of Mexico on TDI-Brooks Vessel Brooks McCall between 2012-07-12 and 2012-07-24

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The final year of a multi-year effort to study Lophelia coral communities in the Gulf of Mexico is occurring on the TDI-Brooks research vessel, Brooks McCall,...

  1. Classification of underwater targets from autonomous underwater vehicle sampled bistatic acoustic scattered fields.

    Science.gov (United States)

    Fischell, Erin M; Schmidt, Henrik

    2015-12-01

    One of the long term goals of autonomous underwater vehicle (AUV) minehunting is to have multiple inexpensive AUVs in a harbor autonomously classify hazards. Existing acoustic methods for target classification using AUV-based sensing, such as sidescan and synthetic aperture sonar, require an expensive payload on each outfitted vehicle and post-processing and/or image interpretation. A vehicle payload and machine learning classification methodology using bistatic angle dependence of target scattering amplitudes between a fixed acoustic source and target has been developed for onboard, fully autonomous classification with lower cost-per-vehicle. To achieve the high-quality, densely sampled three-dimensional (3D) bistatic scattering data required by this research, vehicle sampling behaviors and an acoustic payload for precision timed data acquisition with a 16 element nose array were demonstrated. 3D bistatic scattered field data were collected by an AUV around spherical and cylindrical targets insonified by a 7-9 kHz fixed source. The collected data were compared to simulated scattering models. Classification and confidence estimation were shown for the sphere versus cylinder case on the resulting real and simulated bistatic amplitude data. The final models were used for classification of simulated targets in real time in the LAMSS MOOS-IvP simulation package [M. Benjamin, H. Schmidt, P. Newman, and J. Leonard, J. Field Rob. 27, 834-875 (2010)].

  2. Underwater striling engine design with modified one-dimensional model

    Directory of Open Access Journals (Sweden)

    Daijin Li

    2015-05-01

    Full Text Available Stirling engines are regarded as an efficient and promising power system for underwater devices. Currently, many researches on one-dimensional model is used to evaluate thermodynamic performance of Stirling engine, but in which there are still some aspects which cannot be modeled with proper mathematical models such as mechanical loss or auxiliary power. In this paper, a four-cylinder double-acting Stirling engine for Unmanned Underwater Vehicles (UUVs is discussed. And a one-dimensional model incorporated with empirical equations of mechanical loss and auxiliary power obtained from experiments is derived while referring to the Stirling engine computer model of National Aeronautics and Space Administration (NASA. The P-40 Stirling engine with sufficient testing results from NASA is utilized to validate the accuracy of this one-dimensional model. It shows that the maximum error of output power of theoretical analysis results is less than 18% over testing results, and the maximum error of input power is no more than 9%. Finally, a Stirling engine for UUVs is designed with Schmidt analysis method and the modified one-dimensional model, and the results indicate this designed engine is capable of showing desired output power.

  3. Reviving a neglected celestial underwater polarization compass for aquatic animals.

    Science.gov (United States)

    Waterman, Talbot H

    2006-02-01

    Substantial in situ measurements on clear days in a variety of marine environments at depths in the water down to 200 m have demonstrated the ubiquitous daytime presence of sun-related e-vector (=plane of polarization) patterns. In most lines of sight the e-vectors tilt from horizontal towards the sun at angles equal to the apparent underwater refracted zenith angle of the sun. A maximum tilt-angle of approximately 48.5 degrees , is reached in horizontal lines of sight at 90 degrees to the sun's bearing (the plane of incidence). This tilt limit is set by Snell's window, when the sun is on the horizon. The biological literature since the 1980s has been pervaded with assumptions that daytime aquatic e-vectors are mainly horizontal. This review attempts to set the record straight concerning the potential use of underwater e-vectors as a visual compass and to reopen the field to productive research on aquatic animals' orientation and navigation.

  4. Multiple shell pressure vessel

    International Nuclear Information System (INIS)

    Wedellsborg, B.W.

    1988-01-01

    A method is described of fabricating a pressure vessel comprising the steps of: attaching a first inner pressure vessel having means defining inlet and outlet openings to a top flange, placing a second inner pressure vessel, having means defining inlet and outlet opening, concentric with and spaced about the first inner pressure vessel and attaching the second inner pressure vessel to the top flange, placing an outer pressure vessel, having inlet and outlet openings, concentric with and spaced apart about the second inner pressure vessel and attaching the outer pressure vessel to the top flange, attaching a generally cylindrical inner inlet conduit and a generally cylindrical inner outlet conduit respectively to the inlet and outlet openings in the first inner pressure vessel, attaching a generally cylindrical outer inlet conduit and a generally cylindrical outer outlet conduit respectively to the inlet and outlet opening in the second inner pressure vessel, heating the assembled pressure vessel to a temperature above the melting point of a material selected from the group, lead, tin, antimony, bismuth, potassium, sodium, boron and mixtures thereof, filling the space between the first inner pressure vessel and the second inner pressure vessel with material selected from the group, filling the space between the second inner pressure vessel and the outer pressure vessel with material selected from the group, and pressurizing the material filling the spaces between the pressure vessels to a predetermined pressure, the step comprising: pressurizing the spaces to a pressure whereby the wall of the first inner pressure vessel is maintained in compression during steady state operation of the pressure vessel

  5. Use of Zircaloy 4 material for the pressure vessels of hot and cold neutron sources and beam tubes for research reactors

    International Nuclear Information System (INIS)

    Scheuer, A.; Gutsmiedl, E.

    1999-01-01

    The material Zircaloy 4 can be used for the pressure retaining walls for the cold and hot neutron sources and beam tubes. For the research reactor FRM-II of the Technical University Munich, Germany, the material Zircaloy 4 were chosen for the vessels of the cold and hot neutron source and for the beam tube No. 6. The sheets and forgings of Zircaloy 4 were examined in the temperature range between -256 deg. C and 250 deg. C. The thickness of the sheets are 3, 4, 5 and 10 mm, the maximum diameter of the forgings was 560 mm. This great forging diameters are not be treated in the ASTM rule B 351 for nuclear material, so a special approval with independent experts was necessary. The requirements for the material examinations were specified in a material specification and material test sheets which based on the ASTM rules B 351 and B 352 with additional restriction and additional requirements of the basic safety concept for nuclear power plants in Germany, which was take into consideration in the nuclear licensing procedure. Charpy-V samples were carried out in the temperature range between -256 deg. C and 150 deg. C to get more information on the ductile behaviour of the Zircaloy 4. The results of the sheet examination confirm the requirements of the specifications, the results of the forging examination in the tangential testing direction are lower than specified and expected for the tensile strength. The axial and transverse values confirm the specification requirements. For the strength calculation of the pressure retaining wall a reduced material value for the forgings has to take into consideration. The material behaviour of Zircaloy 4 under irradiation up to a fluence of ∼ 1x10 22 n/cm 2 was investigated. The loss of ductility was determined. As an additional criteria the variation of the fracture toughness was studies. Fracture mechanic calculations of the material were carried out in the licensing procedure with the focus to fulfill the leak before rupture

  6. Use of Zircaloy 4 material for the pressure vessels of hot and cold neutron sources and beam tubes for research reactors

    International Nuclear Information System (INIS)

    Gutsmiedl, Erwin

    2001-01-01

    The material Zircaloy 4 can be used for the pressure retaining walls for the cold and hot neutron sources and beam tubes. For the research reactor FRM-II of the Technical University Munich, Germany, the material Zircaloy 4 were chosen for the vessels of the cold and hot neutron source and for the beam tube No. 6. The sheets and forgings of Zircaloy 4 were examined in the temperature range between -256degC and 250degC. The thickness of the sheets are 3, 4, 5 and 10 mm, the maximum diameter of the forgings was 560 mm. This great forging diameters are not be treated in the ASTM rule B 351 for nuclear material, so a special approval with independent experts was necessary. The requirements for the material examinations were specified in a material specification and material test sheets which based on the ASTM rules B 351 and B 352 with additional restriction and additional requirements of the basic safety concept for nuclear power plants in Germany, which was taken into consideration in the nuclear licensing procedure. Charpy-V samples were carried out in the temperature range between -256degC and 150degC to get more information on the ductile behaviour of the Zircaloy 4. The results of the sheet examination confirm the requirements of the specifications, the results of the forging examination in the tangential testing direction are lower than specified and expected for the tensile strength. The axial and transverse values confirm the specification requirements. For the strength calculation of the pressure retaining wall a reduced material value for the forgings has to taken into consideration. The material behaviour of Zircaloy 4 under irradiation up to a fluence of ∼1·10 22 n/cm 2 was investigated. The loss of ductility was determined. As an additional criteria the variation of the fracture toughness was studies. Fracture mechanic calculations of the material were carried out in the licensing procedure with the focus to fulfill the leak before rupture criteria of

  7. 'Surveyor': An Underwater System for Threat Material Detection

    International Nuclear Information System (INIS)

    Valkovic, Vladivoj; Sudac, Davorin; Nad, Karlo; Obhodas, Jasmina; Matika, Dario; Kollar, Robert

    2010-01-01

    The bottoms of the coastal seas, and oceans as well, are contaminated by many man-made objects including a variety of ammunition. This contamination is world wide spread with some areas being highly polluted presenting a serious threat to local population and to visitors as well. All littoral nations are investing lots of effort into the remediation of their coastal areas. Once the presence of the anomaly on the bottom of the shallow coastal sea water is confirmed (by visual identification and by using one or several sensors, namely magnetometer, sonar and optical cameras) it is necessary to establish if it contains explosive/chemical warfare charge. In our work we propose this to be performed by using neutron sensor installed within an underwater vessel - 'Surveyor'. When positioned above the object, or to its side, the system inspects the object for the presence of the threat material by using alpha particle tagged neutrons from the sealed tube d+t neutron generator. (author)

  8. Hydrodynamic Coefficients Identification and Experimental Investigation for an Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Shaorong XIE

    2014-02-01

    Full Text Available Hydrodynamic coefficients are the foundation of unmanned underwater vehicles modeling and controller design. In order to reduce identification complexity and acquire necessary hydrodynamic coefficients for controllers design, the motion of the unmanned underwater vehicle was separated into vertical motion and horizontal motion models. Hydrodynamic coefficients were regarded as mapping parameters from input forces and moments to output velocities and acceleration of the unmanned underwater vehicle. The motion models of the unmanned underwater vehicle were nonlinear and Genetic Algorithm was adopted to identify those hydrodynamic coefficients. To verify the identification quality, velocities and acceleration of the unmanned underwater vehicle was measured using inertial sensor under the same conditions as Genetic Algorithm identification. Curves similarity between measured velocities and acceleration and those identified by Genetic Algorithm were used as optimizing standard. It is found that the curves similarity were high and identified hydrodynamic coefficients of the unmanned underwater vehicle satisfied the measured motion states well.

  9. Efficient Weibull channel model for salinity induced turbulent underwater wireless optical communications

    KAUST Repository

    Oubei, Hassan M.; Zedini, Emna; Elafandy, Rami T.; Kammoun, Abla; Ng, Tien Khee; Alouini, Mohamed-Slim; Ooi, Boon S.

    2017-01-01

    Recent advances in underwater wireless optical communications necessitate a better understanding of the underwater channel. We propose the Weibull model to characterize the fading of salinity induced turbulent underwater wireless optical channels

  10. Underwater videography and photography in Gulf of Kachchh. Sponsored by Gujarat Ecological Society, Vadodara, Gujarat

    Digital Repository Service at National Institute of Oceanography (India)

    Marine Archaeology Centre (MAC) has been carrying out underwater explorations and excavations of ancient ports and sunken shipwrecks to preserve underwater cultural heritage. MAC has the infrastructure facility to carry out underwater investigations...

  11. Immunological quality and performance of tumor vessel-targeting CAR-T cells prepared by mRNA-EP for clinical research

    Directory of Open Access Journals (Sweden)

    Kanako Inoo

    2016-01-01

    Full Text Available We previously reported that tumor vessel-redirected T cells, which were genetically engineered with chimeric antigen receptor (CAR specific for vascular endothelial growth factor receptor 2 (VEGFR2, demonstrated significant antitumor effects in various murine solid tumor models. In the present study, we prepared anti-VEGFR2 CAR-T cells by CAR-coding mRNA electroporation (mRNA-EP and analyzed their immunological characteristics and functions for use in clinical research. The expression of anti-VEGFR2 CAR on murine and human T cells was detected with approximately 100% efficiency for a few days, after peaking 6–12 hours after mRNA-EP. Triple transfer of murine anti-VEGFR2 CAR-T cells into B16BL6 tumor-bearing mice demonstrated an antitumor effect comparable to that for the single transfer of CAR-T cells engineered with retroviral vector. The mRNA-EP did not cause any damage or defects to human T-cell characteristics, as determined by viability, growth, and phenotypic parameters. Additionally, two kinds of human anti-VEGFR2 CAR-T cells, which expressed different CAR construction, differentiated to effector phase with cytokine secretion and cytotoxic activity in antigen-specific manner. These results indicate that our anti-VEGFR2 CAR-T cells prepared by mRNA-EP have the potential in terms of quality and performance to offer the prospect of safety and efficacy in clinical research as cellular medicine.

  12. Underwater laser beam welding of Alloy 690

    International Nuclear Information System (INIS)

    Hino, Takehisa; Tamura, Masataka; Kono, Wataru; Kawano, Shohei; Yoda, Masaki

    2009-01-01

    Stress Corrosion Clacking (SCC) has been reported at Alloy 600 welds between nozzles and safe-end in Pressurized Water Reactor (PWR) plant. Alloy 690, which has higher chromium content than Alloy 600, has been applied for cladding on Alloy 600 welds for repairing damaged SCC area. Toshiba has developed Underwater Laser Beam Welding technique. This method can be conducted without draining, so that the repairing period and the radiation exposure during the repair can be dramatically decreased. In some old PWRs, high-sulfur stainless steel is used as the materials for this section. It has a high susceptibility of weld cracks. Therefore, the optimum welding condition of Alloy 690 on the high-sulfur stainless steel was investigated with our Underwater Laser Beam Welding unit. Good cladding layer, without any crack, porosity or lack of fusion, could be obtained. (author)

  13. Cymbal and BB underwater transducers and arrays

    Energy Technology Data Exchange (ETDEWEB)

    Newnham, R.E.; Zhang, J.; Alkoy, S.; Meyer, R.; Hughes, W.J.; Hladky-Hennion, A.C.; Cochran, J.; Markley, D. [Materials Research Laboratory, Penn State University, University Park, PA 16802 (United States)

    2002-09-01

    The cymbal is a miniaturized class V flextensional transducer that was developed for use as a shallow water sound projector and receiver. Single elements are characterized by high Q, low efficiency, and medium power output capability. Its low cost and thin profile allow the transducer to be assembled into large flexible arrays. Efforts were made to model both single elements and arrays using the ATILA code and the integral equation formulation (EQI).Millimeter size microprobe hydrophones (BBs) have been designed and fabricated from miniature piezoelectric hollow ceramic spheres for underwater applications such as mapping acoustic fields of projectors, and flow noise sensors for complex underwater structures. Green spheres are prepared from soft lead zirconate titanate powders using a coaxial nozzle slurry process. A compact hydrophone with a radially-poled sphere is investigated using inside and outside electrodes. Characterization of these hydrophones is done through measurement of hydrostatic piezoelectric charge coefficients, free field voltage sensitivities and directivity beam patterns. (orig.)

  14. Equipment and appliances for underwater operations. Pt. 2

    International Nuclear Information System (INIS)

    Krueger, P.

    1976-01-01

    The 6/75 edition of 'mt' reported on the 'ARGE underwater appliances' and the study on 'design development of appliances and equipment for underwater use' in a brief summary. One of these designs, the 'unmanned DSWS underwater appliance' was described in detail. The present article describes three further design developments mentioned in the above study and which are based on unmanned appliances connected to the mother-ship. These designs were developed by Preussag-Meerestechnik. (orig.) [de

  15. Natural and bio-inspired underwater adhesives: Current progress and new perspectives

    Science.gov (United States)

    Cui, Mengkui; Ren, Susu; Wei, Shicao; Sun, Chengjun; Zhong, Chao

    2017-11-01

    Many marine organisms harness diverse protein molecules as underwater adhesives to achieve strong and robust interfacial adhesion under dynamic and turbulent environments. Natural underwater adhesion phenomena thus provide inspiration for engineering adhesive materials that can perform in water or high-moisture settings for biomedical and industrial applications. Here we review examples of biological adhesives to show the molecular features of natural adhesives and discuss how such knowledge serves as a heuristic guideline for the rational design of biologically inspired underwater adhesives. In view of future bio-inspired research, we propose several potential opportunities, either in improving upon current L-3, 4-dihydroxyphenylalanine-based and coacervates-enabled adhesives with new features or engineering conceptually new types of adhesives that recapitulate important characteristics of biological adhesives. We underline the importance of viewing natural adhesives as dynamic materials, which owe their outstanding performance to the cellular coordination of protein expression, delivery, deposition, assembly, and curing of corresponding components with spatiotemporal control. We envision that the emerging synthetic biology techniques will provide great opportunities for advancing both fundamental and application aspects of underwater adhesives.

  16. Natural and bio-inspired underwater adhesives: Current progress and new perspectives

    Directory of Open Access Journals (Sweden)

    Mengkui Cui

    2017-11-01

    Full Text Available Many marine organisms harness diverse protein molecules as underwater adhesives to achieve strong and robust interfacial adhesion under dynamic and turbulent environments. Natural underwater adhesion phenomena thus provide inspiration for engineering adhesive materials that can perform in water or high-moisture settings for biomedical and industrial applications. Here we review examples of biological adhesives to show the molecular features of natural adhesives and discuss how such knowledge serves as a heuristic guideline for the rational design of biologically inspired underwater adhesives. In view of future bio-inspired research, we propose several potential opportunities, either in improving upon current L-3, 4-dihydroxyphenylalanine-based and coacervates-enabled adhesives with new features or engineering conceptually new types of adhesives that recapitulate important characteristics of biological adhesives. We underline the importance of viewing natural adhesives as dynamic materials, which owe their outstanding performance to the cellular coordination of protein expression, delivery, deposition, assembly, and curing of corresponding components with spatiotemporal control. We envision that the emerging synthetic biology techniques will provide great opportunities for advancing both fundamental and application aspects of underwater adhesives.

  17. Effects of light refraction on the accuracy of camera calibration and reconstruction in underwater motion analysis.

    Science.gov (United States)

    Kwon, Young-Hoo; Casebolt, Jeffrey B

    2006-07-01

    One of the most serious obstacles to accurate quantification of the underwater motion of a swimmer's body is image deformation caused by refraction. Refraction occurs at the water-air interface plane (glass) owing to the density difference. Camera calibration-reconstruction algorithms commonly used in aquatic research do not have the capability to correct this refraction-induced nonlinear image deformation and produce large reconstruction errors. The aim of this paper is to provide a thorough review of: the nature of the refraction-induced image deformation and its behaviour in underwater object-space plane reconstruction; the intrinsic shortcomings of the Direct Linear Transformation (DLT) method in underwater motion analysis; experimental conditions that interact with refraction; and alternative algorithms and strategies that can be used to improve the calibration-reconstruction accuracy. Although it is impossible to remove the refraction error completely in conventional camera calibration-reconstruction methods, it is possible to improve the accuracy to some extent by manipulating experimental conditions or calibration frame characteristics. Alternative algorithms, such as the localized DLT and the double-plane method are also available for error reduction. The ultimate solution for the refraction problem is to develop underwater camera calibration and reconstruction algorithms that have the capability to correct refraction.

  18. MEDITERRANEAN: Underwater neutrinos get off the ground

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Now funded is the initial stage of NESTOR, an imaginative new programme for a dedicated underwater neutrino astroparticle physics laboratory. Located in the international waters off the southernmost corner of continental Europe near the town of Pylos in S.W. Greece, NESTOR (NEutrinos from Supernovae and TeV sources Ocean Range) recalls the wise king of Pylos who counselled the Greeks during the Trojan war, an excellent tradition for new scientific goals of detecting neutrinos

  19. Inspecting the inside of underwater hull

    Science.gov (United States)

    Valkovic, Vladivoj; Sudac, Davorin

    2009-05-01

    In order to demonstrate the possibility of identifying the material within ship's underwater hull, sunken ships and other objects on the sea floor tests with the 14 MeV sealed tube neutron generator incorporated inside a small submarine submerged in the test basin filled with sea water have been performed. Results obtained for inspection of diesel fuel and explosive presence behind single and double hull constructions are presented.

  20. Underwater bipedal locomotion by octopuses in disguise.

    Science.gov (United States)

    Huffard, Christine L; Boneka, Farnis; Full, Robert J

    2005-03-25

    Here we report bipedal movement with a hydrostatic skeleton. Two species of octopus walk on two alternating arms using a rolling gait and appear to use the remaining six arms for camouflage. Octopus marginatus resembles a coconut, and Octopus (Abdopus) aculeatus, a clump of floating algae. Using underwater video, we analyzed the kinematics of their strides. Each arm was on the sand for more than half of the stride, qualifying this behavior as a form of walking.

  1. Role of Confined Water in Underwater Adhesion

    Science.gov (United States)

    Dhinojwala, Ali

    Surface bound water is a strong deterrent for forming strong bonds between two surfaces underwater and expelling that bound water is important for strong adhesion. I will discuss examples of different strategies used by geckos, spiders, and mussels to handle this last layer of bound water. Recent results using infrared-visible sum frequency generation spectroscopy to probe the structure of this bound water will be discussed. National Science Foundation.

  2. Probabilistic retinal vessel segmentation

    Science.gov (United States)

    Wu, Chang-Hua; Agam, Gady

    2007-03-01

    Optic fundus assessment is widely used for diagnosing vascular and non-vascular pathology. Inspection of the retinal vasculature may reveal hypertension, diabetes, arteriosclerosis, cardiovascular disease and stroke. Due to various imaging conditions retinal images may be degraded. Consequently, the enhancement of such images and vessels in them is an important task with direct clinical applications. We propose a novel technique for vessel enhancement in retinal images that is capable of enhancing vessel junctions in addition to linear vessel segments. This is an extension of vessel filters we have previously developed for vessel enhancement in thoracic CT scans. The proposed approach is based on probabilistic models which can discern vessels and junctions. Evaluation shows the proposed filter is better than several known techniques and is comparable to the state of the art when evaluated on a standard dataset. A ridge-based vessel tracking process is applied on the enhanced image to demonstrate the effectiveness of the enhancement filter.

  3. Study on underwater plasma arc cutting technology

    International Nuclear Information System (INIS)

    Yada, Toshio; Nakamura, Uhachiro; Tomidokoro, Sakae; Fukuzawa, Mitsuo

    1980-01-01

    The zirconium alloy tube of the impile creep test facility had been subjected to inner pressure in the Japan Material Testing Reactor (JMTR) environment. In the near future, it will be necessary to dismantle the facility and to take out the tube for such examinations as irradiation effects on material properties. In order to establish the dismantling technology for the radioactive facility, a study on underwater plasma arc cutting has been carried out since 1977. Primarily, optimum underwater cutting sequence and conditions were studied in details for developing the remote control handling and the cutting system. Further, the amounts of particles suspended in water as well as those contained in bubbled gas were quantitatively analyzed for developing a safe removal system for contaminants which were produced by cutting the radioactive material. As a result of this study, it has been concluded that the underwater plasma arc cutting method is generally suitable and effective for dismantling such radioactive material as the impile creep test facility of the JMTR. (author)

  4. Underwater Acoustic Target Tracking: A Review

    Science.gov (United States)

    Han, Ying; Fan, Liying

    2018-01-01

    Advances in acoustic technology and instrumentation now make it possible to explore marine resources. As a significant component of ocean exploration, underwater acoustic target tracking has aroused wide attention both in military and civil fields. Due to the complexity of the marine environment, numerous techniques have been proposed to obtain better tracking performance. In this paper, we survey over 100 papers ranging from innovative papers to the state-of-the-art in this field to present underwater tracking technologies. Not only the related knowledge of acoustic tracking instrument and tracking progress is clarified in detail, but also a novel taxonomy method is proposed. In this paper, algorithms for underwater acoustic target tracking are classified based on the methods used as: (1) instrument-assisted methods; (2) mode-based methods; (3) tracking optimization methods. These algorithms are compared and analyzed in the aspect of dimensions, numbers, and maneuvering of the tracking target, which is different from other survey papers. Meanwhile, challenges, countermeasures, and lessons learned are illustrated in this paper. PMID:29301318

  5. Underwater detection by using ultrasonic sensor

    Science.gov (United States)

    Bakar, S. A. A.; Ong, N. R.; Aziz, M. H. A.; Alcain, J. B.; Haimi, W. M. W. N.; Sauli, Z.

    2017-09-01

    This paper described the low cost implementation of hardware and software in developing the system of ultrasonic which can visualize the feedback of sound in the form of measured distance through mobile phone and monitoring the frequency of detection by using real time graph of Java application. A single waterproof transducer of JSN-SR04T had been used to determine the distance of an object based on operation of the classic pulse echo detection method underwater. In this experiment, the system was tested by placing the housing which consisted of Arduino UNO, Bluetooth module of HC-06, ultrasonic sensor and LEDs at the top of the box and the transducer was immersed in the water. The system which had been tested for detection in vertical form was found to be capable of reporting through the use of colored LEDs as indicator to the relative proximity of object distance underwater form the sensor. As a conclusion, the system can detect the presence of an object underwater within the range of ultrasonic sensor and display the measured distance onto the mobile phone and the real time graph had been successfully generated.

  6. Afocal viewport optics for underwater imaging

    Science.gov (United States)

    Slater, Dan

    2014-09-01

    A conventional camera can be adapted for underwater use by enclosing it in a sealed waterproof pressure housing with a viewport. The viewport, as an optical interface between water and air needs to consider both the camera and water optical characteristics while also providing a high pressure water seal. Limited hydrospace visibility drives a need for wide angle viewports. Practical optical interfaces between seawater and air vary from simple flat plate windows to complex water contact lenses. This paper first provides a brief overview of the physical and optical properties of the ocean environment along with suitable optical materials. This is followed by a discussion of the characteristics of various afocal underwater viewport types including flat windows, domes and the Ivanoff corrector lens, a derivative of a Galilean wide angle camera adapter. Several new and interesting optical designs derived from the Ivanoff corrector lens are presented including a pair of very compact afocal viewport lenses that are compatible with both in water and in air environments and an afocal underwater hyper-hemispherical fisheye lens.

  7. Environmental effects on underwater optical transmission

    Science.gov (United States)

    Chu, Peter C.; Breshears, Brian F.; Cullen, Alexander J.; Hammerer, Ross F.; Martinez, Ramon P.; Phung, Thai Q.; Margolina, Tetyana; Fan, Chenwu

    2017-05-01

    Optical communication/detection systems have potential to get around some limitations of current acoustic communications and detection systems especially increased fleet and port security in noisy littoral waters. Identification of environmental effects on underwater optical transmission is the key to the success of using optics for underwater communication and detection. This paper is to answer the question "What are the transfer and correlation functions that relate measurements of hydrographic to optical parameters?" Hydrographic and optical data have been collected from the Naval Oceanographic Office survey ships with the High Intake Defined Excitation (HIDEX) photometer and sea gliders with optical back scattering sensor in various Navy interested areas such as the Arabian Gulf, Gulf of Oman, east Asian marginal seas, and Adriatic Sea. The data include temperature, salinity, bioluminescence, chlorophyll-a fluorescence, transmissivity at two different wavelengths (TRed at 670 nm, TBlue at 490 nm), and back scattering coefficient (bRed at 700 nm, bBlue at 470 nm). Transfer and correlation functions between the hydrographic and optical parameters are obtained. Bioluminescence and fluorescence maxima, transmissivity minimum with their corresponding depths, red and blue laser beam peak attenuation coefficients are identified from the optical profiles. Evident correlations are found between the ocean mixed layer depth and the blue and red laser beam peak attenuation coefficients, bioluminescence and fluorescence maxima in the Adriatic Sea, Arabian Gulf, Gulf of Oman, and Philippine Sea. Based on the observational data, an effective algorithm is recommended for solving the radiative transfer equation (RTE) for predicting underwater laser radiance.

  8. Automatic stabilization of underwater robots in the time manipulation operations

    International Nuclear Information System (INIS)

    Filaretov, V.F.; Koval, E.V.

    1994-01-01

    When carrying out underwater technical works by means of an underwater vehicles having a manipulator it is desirable to perform manipulation operations in the regime of the underwater vehicle hovering above the object without durable and complicated operations up its rigid fixation. Underwater vehicle stabilization is achieved by compensation all the effects on the vehicle caused by the operating manipulator in water medium. This automatic stabilization is formed due to input of the required control signals into corresponding vehicle propellers proportional to calculated components of the generalized forces and moments. The propellers should form stops reacting against effects

  9. Underwater hearing in the great cormorant (Phalacrocorax carbo sinensis)

    DEFF Research Database (Denmark)

    Hansen, Kirstin Anderson; Larsen, Ole Næsbye; Wahlberg, Magnus

    2016-01-01

    The underwater hearing threshold of a great cormorant (Phalacrocroax carbo sinensis) was measured at 2 kHz using psychophysical methods. Previous in-air and underwater testing suggests that cormorants have rather poor in-air hearing compared to other birds of similar size (Johansen, 2016). Prelim......The underwater hearing threshold of a great cormorant (Phalacrocroax carbo sinensis) was measured at 2 kHz using psychophysical methods. Previous in-air and underwater testing suggests that cormorants have rather poor in-air hearing compared to other birds of similar size (Johansen, 2016...

  10. Contour Tracking Control for the REMUS Autonomous Underwater Vehicle

    National Research Council Canada - National Science Library

    Van Reet, Alan R

    2005-01-01

    In the interest of enhancing the capabilities of autonomous underwater vehicles used in US Naval Operations, controlling vehicle position to follow depth contours presents exciting potential for navigation...

  11. Autopilot Using Differential Thrust for ARIES Autonomous Underwater Vehicle

    National Research Council Canada - National Science Library

    Sarton, Christopher

    2003-01-01

    .... Unfortunately, communication antennas must point to specific satellites in this system and thus underwater vehicles must steer a specific course on the surface during the communication process...

  12. Improvement to reactor vessel

    International Nuclear Information System (INIS)

    1974-01-01

    The vessel described includes a prestressed concrete vessel containing a chamber and a removable cover closing this chamber. The cover is in concrete and is kept in its closed position by main and auxiliary retainers, comprising fittings integral with the concrete of the vessel. The auxiliary retainers pass through the concrete of the cover. This improvement may be applied to BWR, PWR and LMFBR type reactor vessel [fr

  13. ALICE HMPID Radiator Vessel

    CERN Document Server

    2003-01-01

    View of the radiator vessels of the ALICE/HMPID mounted on the support frame. Each HMPID module is equipped with 3 indipendent radiator vessels made out of neoceram and fused silica (quartz) windows glued together. The spacers inside the vessel are needed to stand the hydrostatic pressure. http://alice-hmpid.web.cern.ch/alice-hmpid

  14. Stress analysis of pressure vessels

    International Nuclear Information System (INIS)

    Kim, B.K.; Song, D.H.; Son, K.H.; Kim, K.S.; Park, K.B.; Song, H.K.; So, J.Y.

    1979-01-01

    This interim report contains the results of the effort to establish the stress report preparation capability under the research project ''Stress analysis of pressure vessels.'' 1978 was the first year in this effort to lay the foundation through the acquisition of SAP V structural analysis code and a graphic terminal system for improved efficiency of using such code. Software programming work was developed in pre- and post processing, such as graphic presentation of input FEM mesh geometry and output deformation or mode shope patterns, which was proven to be useful when using the FEM computer code. Also, a scheme to apply fracture mechanics concept was developed in fatigue analysis of pressure vessels. (author)

  15. A Novel Fractional Fourier Transform-Based ASK-OFDM System for Underwater Acoustic Communications

    Directory of Open Access Journals (Sweden)

    Rami Ashri

    2017-12-01

    Full Text Available A key research area in wireless transmission is underwater communications. It has a vital role in applications such as underwater sensor networks (UWSNs and disaster detection. The underwater channel is very unique as compared to other alternatives of transmission channels. It is characterized by path loss, multipath fading, Doppler spread and ambient noise. Thus, the bit error rate (BER is increased to a large extent when compared to its counterpart of cellular communications. Acoustic signals are the current best solution for underwater communications. The use of electromagnetic or optical waves obviously entails a much higher data rate. However, they suffer from high attenuation, absorption or scattering. This paper proposes a novel fractional fast Fourier transform (FrFT—orthogonal frequency division multiplexing (FrFT-OFDM system for underwater acoustic (UWA communication—which employs the amplitude shift keying (ASK modulation technique (FrFT-ASK-OFDM. Specifically, ASK achieves a better bandwidth efficiency as compared to other commonly used modulation techniques, such as quadrature amplitude modulation (QAM and phase shift keying (PSK. In particular, the system proposed in this article can achieve a very promising BER performance, and can reach higher data rates when compared to other systems proposed in the literature. The BER performance of the proposed system is evaluated numerically, and is compared to the corresponding M-ary QAM system in the UWA channel for the same channel conditions. Moreover, the performance of the proposed system is compared to the conventional fast Fourier transform (FFT-OFDM (FFT-OFDM system in the absence and presence of the effect of carrier frequency offset (CFO. Numerical results show that the proposed system outperforms the conventional FFT-based systems for UWA channels, even in channels dominated by CFO. Moreover, the spectral efficiency and data rate of the proposed system are approximately double

  16. Research on the water hammer protection of the long distance water supply project with the combined action of the air vessel and over-pressure relief valve

    International Nuclear Information System (INIS)

    Li, D D; Jiang, J; Zhao, Z; Yi, W S; Lan, G

    2013-01-01

    We take a concrete pumping station as an example in this paper. Through the calculation of water hammer protection with a specific pumping station water supply project, and the analysis of the principle, mathematical models and boundary conditions of air vessel and over-pressure relief valve we show that the air vessel can protect the water conveyance system and reduce the transient pressure damage due to various causes. Over-pressure relief valve can effectively reduce the water hammer because the water column re-bridge suddenly stops the pump and prevents pipeline burst. The paper indicates that the combination set of air vessel and over-pressure relief valve can greatly reduce the quantity of the air valve and can eliminate the water hammer phenomenon in the pipeline system due to the vaporization and water column separation and re-bridge. The conclusion could provide a reference for the water hammer protection of long-distance water supply system

  17. Research on the water hammer protection of the long distance water supply project with the combined action of the air vessel and over-pressure relief valve

    Science.gov (United States)

    Li, D. D.; Jiang, J.; Zhao, Z.; Yi, W. S.; Lan, G.

    2013-12-01

    We take a concrete pumping station as an example in this paper. Through the calculation of water hammer protection with a specific pumping station water supply project, and the analysis of the principle, mathematical models and boundary conditions of air vessel and over-pressure relief valve we show that the air vessel can protect the water conveyance system and reduce the transient pressure damage due to various causes. Over-pressure relief valve can effectively reduce the water hammer because the water column re-bridge suddenly stops the pump and prevents pipeline burst. The paper indicates that the combination set of air vessel and over-pressure relief valve can greatly reduce the quantity of the air valve and can eliminate the water hammer phenomenon in the pipeline system due to the vaporization and water column separation and re-bridge. The conclusion could provide a reference for the water hammer protection of long-distance water supply system.

  18. Development of Catamaran Fishing Vessel

    Directory of Open Access Journals (Sweden)

    A. Jamaluddin

    2010-11-01

    Full Text Available Multihull due to a couple of advantages has been the topic of extensive research work in naval architecture. In this study, a series of investigation of fishing vessel to save fuel energy was carried out at ITS. Two types of ship models, monohull (round bilge and hard chine and catamaran, a boat with two hulls (symmetrical and asymmetrical were developed. Four models were produced physically and numerically, tested (towing tank and simulated numerically (CFD code. The results of the two approaches indicated that the catamaran mode might have drag (resistance smaller than those of monohull at the same displacement. A layout of catamaran fishing vessel, proposed here, indicates the freedom of setting the deck equipments for fishing vessel.

  19. High-performance thermal cutting techniques for underwater use

    International Nuclear Information System (INIS)

    Bach, F.W.

    2002-01-01

    Over the past few years, the Institute for Materials Research of the University of Hanover developed a new product family (Contact-Arc-Metal-X) of electrothermal techniques for underwater cutting of metal structures. This CAMX technology comprises contact arc metal cutting by means of a sword-shaped electrode, contact arc metal grinding with a rotating electrode, and contact arc metal drilling with an integrated interlocking mechanism. CAMC is characterized by its capability to cut components with complex structures. Undercuts and cavities constitute no obstacles in the process. CAMG is a technique for straight cutting characterized by its high cutting speeds. CAMD is able to produce countersunk boreholes and holes of any geometry. The integrated tensioning mechanism allows parts to be gripped and transported which could not be handled by conventional gripper systems. (orig.) [de

  20. WODA technical guidance on underwater sound from dredging

    NARCIS (Netherlands)

    Thomsen, F.; Borsani, F.; Clarke, D.; Jong, C. de; Wit, P. de; Goethals, F.; Holtkamp, M.; Martin, E.S.; Spadaro, P.; Raalte, G. van; Victor, G.Y.V.; Jensen, A.

    2016-01-01

    The World Organization of Dredging Associations (WODA) has identified underwater sound as an environmental issue that needs further consideration. A WODA Expert Group on Underwater Sound (WEGUS) prepared a guidance paper in 2013 on dredging sound, including a summary of potential impacts on aquatic

  1. Evaluating the SCC resistance of underwater welds in sodium tetrathionate

    International Nuclear Information System (INIS)

    White, R.A.; Angeliu, T.M.

    1997-01-01

    The susceptibility of welds to stress corrosion cracking (SCC) is enhanced by the surface residual tensile stresses generated by the typical welding process. However, underwater plasma transferred arc (PTA) welding has been shown to produce compressive surface residual stresses, an encouraging result if repairs of cracked boiling water reactor (BWR) components are to be made without further endangering them to SCC. This program was designed to verify that underwater PTA welds are resistant to SCC and to determine if underwater PTA welding could mitigate SCC in potentially susceptible welds. This was achieved by exposing various welds on solution annealed (SA) and SA + thermally sensitized 304 stainless steel at 25 C in a solution of 1.5 gm/liter of sodium sulfide added to 0.05M sodium tetrathionate, titrated to a pH of 1.25 with H 2 SO 4 . The autogeneous welds were produced using gas tungsten arc (GTA) and plasma transferred arc (PTA) welding under atmospheric conditions, and PTA welding underwater. After 1 hour of sodium tetrathionate exposure, GTA and air PTA welds exhibited SCC while the underwater PTA weld heat affected zones were more resistant. Underwater PTA welds bisecting a GTA weld eliminated the cracking in the GTA weld heat affected zone under certain conditions. The lack of IG cracking in the region influenced by the underwater PTA weld is consistent with the measurement of compressive surface residual stresses inherent to the underwater welding process

  2. Remarks on the observability of single beacon underwater navigation

    DEFF Research Database (Denmark)

    Jouffroy, Jerome; Ross, Andrew

    This paper contributes a simple and intuitive result in the analysis of underwater navigation using a single ranging beacon. This analysis should help with the design of small and lightweight underwater vehicles by reducing the amount of instrumentation required for accurate navigation. The concept...

  3. Underwater laser cladding and seal welding for INCONEL 52

    International Nuclear Information System (INIS)

    Tamura, Masataka; Kouno, Wataru; Makino, Yoshinobu; Kawano, Shohei; Yoda, Masaki

    2007-01-01

    Recently, stress corrosion cracking (SCC) has been observed at aged components of nuclear power plants under water environment and high exposure of radiation. Toshiba has been developing both an underwater laser welding directly onto surface of the aged components as maintenance and repair techniques. This paper reports underwater laser cladding and seal welding for INCONEL 52. (author)

  4. Underwater methods for study of salmonids in the Intermountain West

    Science.gov (United States)

    Russell F. Thurow

    1994-01-01

    This guide describes underwater methods using snorkeling gear to study fish populations in flowing waters of the Intermountain West. It outlines procedures for estimating salmonid abundance and habitat use and provides criteria for identifying and estimating the size of fish underwater.

  5. The WODA guidance paper on underwater sound from dredging (abstract)

    NARCIS (Netherlands)

    Thomsen, F.; Borsani, F.; Clarke, D.; Jong, C.A.F. de; Witt, P. de; Holtkamp, M.; Goethals, F.; San Martin, E.; Spadaro, P.; Raalte, G. van; Jensen, A.

    2013-01-01

    The World Organisation of Dredging Associations (WODA) has identified underwater sound as an environmental issue that needs further consideration. A WODA Expert Group on Underwater Sound (WEGUS) was established to provide a guidance paper on dredging sound, impact on aquatic biota and advice on

  6. Optimization of an Intelligent Controller for an Unmanned Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    M. Fauzi Nor Shah

    2011-08-01

    Full Text Available Underwater environment poses a difficult challenge for autonomous underwater navigation. A standard problem of underwater vehicles is to maintain it position at a certain depth in order to perform desired operations. An effective controller is required for this purpose and hence the design of a depth controller for an unmanned underwater vehicle is described in this paper. The control algorithm is simulated by using the marine guidance navigation and control simulator. The project shows a radial basis function metamodel can be used to tune the scaling factors of a fuzzy logic controller. By using offline optimization approach, a comparison between genetic algorithm and metamodeling has been done to minimize the integral square error between the set point and the measured depth of the underwater vehicle. The results showed that it is possible to obtain a reasonably good error using metamodeling approach in much a shorter time compared to the genetic algorithm approach.

  7. A man-made object detection for underwater TV

    Science.gov (United States)

    Cheng, Binbin; Wang, Wenwu; Chen, Yao

    2018-03-01

    It is a great challenging task to complete an automatic search of objects underwater. Usually the forward looking sonar is used to find the target, and then the initial identification of the target is completed by the side-scan sonar, and finally the confirmation of the target is accomplished by underwater TV. This paper presents an efficient method for automatic extraction of man-made sensitive targets in underwater TV. Firstly, the image of underwater TV is simplified with taking full advantage of the prior knowledge of the target and the background; then template matching technology is used for target detection; finally the target is confirmed by extracting parallel lines on the target contour. The algorithm is formulated for real-time execution on limited-memory commercial-of-the-shelf platforms and is capable of detection objects in underwater TV.

  8. Application of Underwater Shock Wave Focusing to the Development of Extracorporeal Shock Wave Lithotripsy

    Science.gov (United States)

    Takayama, Kazuyoshi

    1993-05-01

    This paper describes a summary of a research project for the development of extracorporeal shock wave lithotripsy (ESWL), which has been carried out, under close collaboration between the Shock Wave Research Center of Tohoku University and the School of Medicine, Tohoku University. The ESWL is a noninvasive clinical treatment of disintegrating human calculi and one of the most peaceful applications of shock waves. Underwater spherical shock waves were generated by explosion of microexplosives. Characteristics of the underwater shock waves and of ultrasound focusing were studied by means of holographic interferometric flow visualization and polyvinyliden-difluoride (PVDF) pressure transducers. These focused pressures, when applied to clinical treatments, could effectively and noninvasively disintegrate urinary tract stones or gallbladder stones. However, despite clincal success, tissue damage occurs during ESWL treatments, and the possible mechanism of tissue damage is briefly described.

  9. Argonne Liquid-Metal Advanced Burner Reactor : components and in-vessel system thermal-hydraulic research and testing experience - pathway forward.

    Energy Technology Data Exchange (ETDEWEB)

    Kasza, K.; Grandy, C.; Chang, Y.; Khalil, H.; Nuclear Engineering Division

    2007-06-30

    This white paper provides an overview and status report of the thermal-hydraulic nuclear research and development, both experimental and computational, conducted predominantly at Argonne National Laboratory. Argonne from the early 1970s through the early 1990s was the Department of Energy's (DOE's) lead lab for thermal-hydraulic development of Liquid Metal Reactors (LMRs). During the 1970s and into the mid-1980s, Argonne conducted thermal-hydraulic studies and experiments on individual reactor components supporting the Experimental Breeder Reactor-II (EBR-II), Fast Flux Test Facility (FFTF), and the Clinch River Breeder Reactor (CRBR). From the mid-1980s and into the early 1990s, Argonne conducted studies on phenomena related to forced- and natural-convection thermal buoyancy in complete in-vessel models of the General Electric (GE) Prototype Reactor Inherently Safe Module (PRISM) and Rockwell International (RI) Sodium Advanced Fast Reactor (SAFR). These two reactor initiatives involved Argonne working closely with U.S. industry and DOE. This paper describes the very important impact of thermal hydraulics dominated by thermal buoyancy forces on reactor global operation and on the behavior/performance of individual components during postulated off-normal accident events with low flow. Utilizing Argonne's LMR expertise and design knowledge is vital to the further development of safe, reliable, and high-performance LMRs. Argonne believes there remains an important need for continued research and development on thermal-hydraulic design in support of DOE's and the international community's renewed thrust for developing and demonstrating the Global Nuclear Energy Partnership (GNEP) reactor(s) and the associated Argonne Liquid Metal-Advanced Burner Reactor (LM-ABR). This white paper highlights that further understanding is needed regarding reactor design under coolant low-flow events. These safety-related events are associated with the transition

  10. Acquisition and tracking for underwater optical communications

    Science.gov (United States)

    Williams, Andrew J.; Laycock, Leslie L.; Griffith, Michael S.; McCarthy, Andrew G.; Rowe, Duncan P.

    2017-10-01

    There is a growing requirement to transfer large volumes of data between underwater platforms. As seawater is transmissive in the visible band, underwater optical communications is an active area of interest since it offers the potential for power efficient, covert and high bandwidth datalinks at short to medium ranges. Short range systems have been successfully demonstrated using sources with low directionality. To realise higher data rates and/or longer ranges, the use of more efficient directional beams is required; by necessity, these must be sufficiently aligned to achieve the required link margin. For mobile platforms, the acquisition and tracking of each node is therefore critical in order to establish and maintain an optical datalink. This paper describes work undertaken to demonstrate acquisition and tracking in a 3D underwater environment. A range of optical sources, beam steering technologies, and tracking sensors have been assessed for suitability. A novel scanning strategy exploiting variable beam divergence was developed to provide robust acquisition whilst minimising acquisition time. A prototype system was assembled and demonstrated in a large water tank. This utilised custom quadrant detectors based on Silicon PhotoMultiplier (SiPM) arrays for fine tracking, and a Wide Field of View (WFoV) sCMOS camera for link acquisition. Fluidic lenses provided dynamic control of beam divergence, and AC modulation/filtering enabled background rejection. The system successfully demonstrated robust optical acquisition and tracking between two nodes with only nanowatt received optical powers. The acquisition time was shown to be dependent on the initial conditions and the transmitted optical power.

  11. Leakage warning system for flexible underwater pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, E; Bernstein, L

    1985-08-01

    Underwater pipelines for unloading oil tankers, e.g. in 30 km distance from the harbour site, are required to be flexible and require supervision. This is done by implementation of oil sensitive sensors between the inner rubber tube and the following impregnated textile layer. The generated sensor signals, influenced by leak oil, have to be wireless transmitted from 150 meters under water to the supervisory station at the coast. Sensor configurations are described, to derive the point of the leakage from the topologized warning signals.

  12. Underwater Sound Propagation from Marine Pile Driving.

    Science.gov (United States)

    Reyff, James A

    2016-01-01

    Pile driving occurs in a variety of nearshore environments that typically have very shallow-water depths. The propagation of pile-driving sound in water is complex, where sound is directly radiated from the pile as well as through the ground substrate. Piles driven in the ground near water bodies can produce considerable underwater sound energy. This paper presents examples of sound propagation through shallow-water environments. Some of these examples illustrate the substantial variation in sound amplitude over time that can be critical to understand when computing an acoustic-based safety zone for aquatic species.

  13. Underwater photography - A visual survey method

    Digital Repository Service at National Institute of Oceanography (India)

    Sharma, R.

    Content-Type text/plain; charset=UTF-8 173 Underwater photography - A visual survey method Rahul Sharma National Institute of Oceanography, Dona Paula, Goa-403004 rsharma@nio.org Introduction “Photography as a means of observing...-sea photographs were those made by Maurice Ewing and his co-workers during cruises on Atlantis in 1940-48. Their subject was the seafloor and their method of clicking was to trigger the camera mechanically when its mounting struck bottom. This is the only...

  14. Water waves generated by underwater explosion

    CERN Document Server

    Mehaute, Bernard Le

    1996-01-01

    This is the first book on explosion-generated water waves. It presents the theoretical foundations and experimental results of the generation and propagation of impulsively generated waves resulting from underwater explosions. Many of the theories and concepts presented herein are applicable to other types of water waves, in particular, tsunamis and waves generated by the fall of a meteorite. Linear and nonlinear theories, as well as experimental calibrations, are presented for cases of deep and shallow water explosions. Propagation of transient waves on dissipative, nonuniform bathymetries to

  15. Radon dynamics in underwater thermal radon therapy

    International Nuclear Information System (INIS)

    Lettner, H.; Hofmann, W.; Winkler, R.; Rolle, R.; Foisner, W.

    1998-01-01

    At a facility for underwater thermal radon therapy in Bad Hofgastein, experiments were carried out with the aim of establishing radon in the air exhaled by the treated patients and of radon decay products on the skin of the patients. The time course of radon concentration in the exhaled air shows a maximum a few minutes after entering the bath, then the Rn concentration remains constant over the remaining time spent in the bath. Taking into account several simplifying assumptions, the average dose to the epidermis from radon daughters is about 50 μGy. (A.K.)

  16. Underwater Activities in the Soviet Union

    Science.gov (United States)

    1975-03-01

    morska , no. 12, 1967, 558-559. Eighty hours under the ice. Poseidon, no. 10 (70), 1967, inside front cover, 433-438, and 465. Fisera, M. A tent, a...Schiffbautechnik, no. 10, 1968. 568-574. 222. Kullnski, J. Meduza-2 underwater base for divers. Technika i gospodarka morska , no. 1, 1969, 44-46. 223...Technika i gospodarka morska , no. 4, 1973, 225-226. Baras, J., S. A. Guljar, and J. N. Kiklewitsch. The Ikhtiandr experiments. Poseidon, no. 4(136

  17. Hydraulic lifter for an underwater drilling rig

    Energy Technology Data Exchange (ETDEWEB)

    Garan' ko, Yu L

    1981-01-15

    A hydraulic lifter is suggested for an underwater drilling rig. It includes a base, hydraulic cylinders for lifting the drilling pipes connected to the clamp holder and hydraulic distributor. In order to simplify the design of the device, the base is made with a hollow chamber connected to the rod cavities and through the hydraulic distributor to the cavities of the hydraulic cylinders for lifting the drilling pipes. The hydraulic distributor is connected to the hydrosphere through the supply valve with control in time or by remote control. The base is equipped with reverse valves whose outlets are on the support surface of the base.

  18. Forecast of Remote Underwater Sensing Technology.

    Science.gov (United States)

    1980-07-01

    Ndgrt o oth NIA ye ’ Suite 709NrtFaothMAO5i Arligton VA 2202Attn: Dave Ho0soci, Chief Enginee~r Attn : Jay W. -arford, Manlager, (617) 563-59)17 (703...0,1305 Attn: Dr. A. Zielinski , Asst. Professor Attn: C. R. B. Lister Faculty of Engineering and (20t) 325-5497 Applied Science (709) 753-1200 Lockheed...157. Zielinski , A.; Barbour, L.; "Swept Carrier Acoustic Underwater Communica- tions," IEEE/MTS Oceans 󈨒, Washington, DC, Sept. 6-8, 1978. 158

  19. Navigation System Fault Diagnosis for Underwater Vehicle

    DEFF Research Database (Denmark)

    Falkenberg, Thomas; Gregersen, Rene Tavs; Blanke, Mogens

    2014-01-01

    This paper demonstrates fault diagnosis on unmanned underwater vehicles (UUV) based on analysis of structure of the nonlinear dynamics. Residuals are generated using dierent approaches in structural analysis followed by statistical change detection. Hypothesis testing thresholds are made signal...... based to cope with non-ideal properties seen in real data. Detection of both sensor and thruster failures are demonstrated. Isolation is performed using the residual signature of detected faults and the change detection algorithm is used to assess severity of faults by estimating their magnitude...

  20. Working underwater: deepwater drilling support by ROV

    Energy Technology Data Exchange (ETDEWEB)

    1958-01-01

    Experience with the drill ships Discoverer Seven Seas and Penrod 78 explains some of the problems associated with the use of remotely operated vehicles (ROVs) for underwater operations. Support services are a bigger problem than depth. The author describes developments, such as the new guidewire methods, side launch A-frame davit, and top hat stabilizing frame. All parts of the ROV system must be of heavy duty design, and operative skill is of paramount importance. The major requirements for deep water ROVs are reliability, fail-safe redundancy, cage deployment, compact size, adequate power, and capacity for heavy intervention work. 8 figures.

  1. Determining spherical lens correction for astronaut training underwater.

    Science.gov (United States)

    Porter, Jason; Gibson, C Robert; Strauss, Samuel

    2011-09-01

    To develop a model that will accurately predict the distance spherical lens correction needed to be worn by National Aeronautics and Space Administration astronauts while training underwater. The replica space suit's helmet contains curved visors that induce refractive power when submersed in water. Anterior surface powers and thicknesses were measured for the helmet's protective and inside visors. The impact of each visor on the helmet's refractive power in water was analyzed using thick lens calculations and Zemax optical design software. Using geometrical optics approximations, a model was developed to determine the optimal distance spherical power needed to be worn underwater based on the helmet's total induced spherical power underwater and the astronaut's manifest spectacle plane correction in air. The validity of the model was tested using data from both eyes of 10 astronauts who trained underwater. The helmet's visors induced a total power of -2.737 D when placed underwater. The required underwater spherical correction (FW) was linearly related to the spectacle plane spherical correction in air (FAir): FW = FAir + 2.356 D. The mean magnitude of the difference between the actual correction worn underwater and the calculated underwater correction was 0.20 ± 0.11 D. The actual and calculated values were highly correlated (r = 0.971) with 70% of eyes having a difference in magnitude of astronauts. The model accurately predicts the actual values worn underwater and can be applied (more generally) to determine a suitable spectacle lens correction to be worn behind other types of masks when submerged underwater.

  2. Underwater welding using remote controlled robots. Development of remote underwater welding technology with a high power YAG laser

    International Nuclear Information System (INIS)

    Miwa, Yasuhiro; Sato, Syuuichi; Kojima, Toshio; Owaki, Katsura; Hirose, Naoya

    2002-01-01

    As components in nuclear power plant have been periodically carried out their inspection and repair to keep their integrity, on radioactive liquid wastes storage facility, because of difficulty on their inspection by human beings, some are remained without inspection, and even when capable of inspection, conversion from human works to remote operations is desired from a viewpoint of their operation efficiency upgrading. For response to these needs, some developments on a technology capable of carrying out inspection of their inside at underwater environment and repairing welding with YAG laser by means of remote operation, have been performed. Remote underwater inspection and repair technology is a combination technology of already applied underwater mobile technique (underwater inspection robot) with underwater YAG laser welding technique which is recently at actual using level. Therefore, this technology is composed of an inspection robot and a repair welding robot. And, testing results using the underwater inspection robot and welding test results using the underwater repair welding robot, were enough preferable to obtain forecasting applicable to actual apparatuses. This technology is especially effective for inspection and repair of inside of nuclear fuel cycle apparatuses and relatively high dose apparatuses, and can be thought to be applicable also to large capacity tanks, tanks dealing with harmful matters, underwater structures, and so on, in general industries. (G.K.)

  3. Enhanced tropospheric BrO over Antarctic sea ice in mid winter observed by MAX-DOAS on board the research vessel Polarstern

    Directory of Open Access Journals (Sweden)

    T. Wagner

    2007-06-01

    Full Text Available We present Multi AXis-Differential Optical Absorption Spectroscopy (MAX-DOAS observations of tropospheric BrO carried out on board the German research vessel Polarstern during the Antarctic winter 2006. Polarstern entered the area of first year sea ice around Antarctica on 24 June 2006 and stayed within this area until 15 August 2006. For the period when the ship cruised inside the first year sea ice belt, enhanced BrO concentrations were almost continuously observed. Outside the first year sea ice belt, typically low BrO concentrations were found. Based on back trajectory calculations we find a positive correlation between the observed BrO differential slant column densities (ΔSCDs and the duration for which the air masses had been in contact with the sea ice surface prior to the measurement. While we can not completely rule out that in several cases the highest BrO concentrations might be located close to the ground, our observations indicate that the maximum BrO concentrations might typically exist in a (possibly extended layer around the upper edge of the boundary layer. Besides the effect of a decreasing pH of sea salt aerosol with altitude and therefore an increase of BrO with height, this finding might be also related to vertical mixing of air from the free troposphere with the boundary layer, probably caused by convection over the warm ocean surface at polynyas and cracks in the ice. Strong vertical gradients of BrO and O3 could also explain why we found enhanced BrO levels almost continuously for the observations within the sea ice. Based on our estimated BrO profiles we derive BrO mixing ratios of several ten ppt, which is slightly higher than many existing observations. Our observations indicate that enhanced BrO concentrations around Antarctica exist about one month earlier than observed by satellite instruments. From detailed radiative transfer simulations we find that MAX-DOAS observations are up to about one order of

  4. Visual examination program of the TRIGA Mark II reactor Vienna with the nuclear underwater telescope

    International Nuclear Information System (INIS)

    Boeck, H.; Hammer, J.; Varga, K.

    1985-12-01

    The visual inspection programm carried out during a three month shut-period at the TRIGA Mark II reactor Vienna is described. Optical inspection of all welds inside the reactor tank was carried out with an underwater telescope developed by the Central Research Institute of Physics, Budapest, Hungary. It is shown that even after 23 years of reactor operation all tank internals were found to be in good condition and minor defects can be easily repaired by remote handling tools. (Author)

  5. Comparison of spatial models for foreground-background segmentation in underwater videos

    OpenAIRE

    Radolko, Martin

    2015-01-01

    The low-level task of foreground-background segregation is an important foundation for many high-level computer vision tasks and has been intensively researched in the past. Nonetheless, unregulated environments usually impose challenging problems, especially the difficult and often neglected underwater environment. There, among others, the edges are blurred, the contrast is impaired and the colors attenuated. Our approach to this problem uses an efficient Background Subtraction algorithm and...

  6. Surveying the Underwater Arcaheological Site of Cape Glaros at Pagasetikos Gulf

    Science.gov (United States)

    Diamanti, E.; Spondylis, E.; Vlachaki, F.; Kolyva, E.

    2017-02-01

    The Hellenic Institute of Marine Archaeology (H.I.M.A.)1 has been conducting an underwater archaeological research in the west coast of southern Pagasetikos Gulf, since 2000. Every year the underwater research focuses on specific archaeological targets that have been recovered during previous field campaigns. The current publication elaborates on the comprehensive documentation of the underwater archaeological site at Cape Glaros, during the 2015 field season, under the direction of the archaeologist Elias Spondylis. The 2015 research campaign was conducted within the framework of the ITACA- Innovation Technologies and Applications for Coastal Archaeological sites European Project (FP7/2007-2013, GA No 606805), at two archaeological sites, namely the Cape Glaros and Metohi. It was among the most important challenges of the project to successfully produce the detailed and accurate 3D mapping of the Cape Glaros site that covers an extended area. Four large concentrations of pottery finds and numerous anchors of different typology have been recorded, that can be dated from the late Hellenistic to the Byzantine periods. This challenge was tackled through the simultaneous implementation of three recording methods; photogrammetry, geodesy and conventional architectural mapping. The workflow of the documentation process, including data acquisition, processing and graphic visualization, along with the derived results are presented below. 1The Hellenic Institute of Marine Archaeology (H.I.M.A.) is a private, non-profit organization, founded in 1973, which undertakes maritime archaeological research under the supervision or in collaboration with the Greek Ministry of Culture. It has over 100 members, with diverse academic credentials, all of whom work, mainly, on a voluntary basis. 3D recording of underwater archaeological sites has been applied to numerous projects that have been carried out by the multidisciplinary team of H.I.M.A. in locations of utmost archaeological

  7. Tumor Blood Vessel Dynamics

    Science.gov (United States)

    Munn, Lance

    2009-11-01

    ``Normalization'' of tumor blood vessels has shown promise to improve the efficacy of chemotherapeutics. In theory, anti-angiogenic drugs targeting endothelial VEGF signaling can improve vessel network structure and function, enhancing the transport of subsequent cytotoxic drugs to cancer cells. In practice, the effects are unpredictable, with varying levels of success. The predominant effects of anti-VEGF therapies are decreased vessel leakiness (hydraulic conductivity), decreased vessel diameters and pruning of the immature vessel network. It is thought that each of these can influence perfusion of the vessel network, inducing flow in regions that were previously sluggish or stagnant. Unfortunately, when anti-VEGF therapies affect vessel structure and function, the changes are dynamic and overlapping in time, and it has been difficult to identify a consistent and predictable normalization ``window'' during which perfusion and subsequent drug delivery is optimal. This is largely due to the non-linearity in the system, and the inability to distinguish the effects of decreased vessel leakiness from those due to network structural changes in clinical trials or animal studies. We have developed a mathematical model to calculate blood flow in complex tumor networks imaged by two-photon microscopy. The model incorporates the necessary and sufficient components for addressing the problem of normalization of tumor vasculature: i) lattice-Boltzmann calculations of the full flow field within the vasculature and within the tissue, ii) diffusion and convection of soluble species such as oxygen or drugs within vessels and the tissue domain, iii) distinct and spatially-resolved vessel hydraulic conductivities and permeabilities for each species, iv) erythrocyte particles advecting in the flow and delivering oxygen with real oxygen release kinetics, v) shear stress-mediated vascular remodeling. This model, guided by multi-parameter intravital imaging of tumor vessel structure

  8. Maury Journals - German Vessels

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — German vessels observations, after the 1853 Brussels Conference that set International Maritime Standards, modeled after Maury Marine Standard Observations.

  9. Oceanographic and fisheries data collected from NOAA and academic research vessels, and commercial menhaden vessels in Gulf of Mexico from 1988-06-14 to 1991-06-22 (NCEI Accession 0156304)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic and fisheries data were collected during 1988 through 1991 through a multiagency research project to develop a remote sensing system to provide near...

  10. Underwater sediment-contact radiation survey method

    International Nuclear Information System (INIS)

    Lee, D.R.; St. Aubin, M.; Welch, S.J.

    1991-01-01

    The authors are striving to produce a practical system for mapping lateral distributions in gamma activity on submerged sediments. This is in response to the need for quality control and interpretation of data obtainable by sediment sampling and analyses near nuclear utilities. A prototype gamma probe has been constructed and tested. The prototype is essentially a background survey meter packaged in a 53-cm-long x 5.4-cm-diam waterproof vehicle. This usage-shaped vehicle is connected to a cable for towing in contact with bottom sediments of lakes, rivers, and coastal waters. This vehicle, or sediment probe as it is called, was initially developed for measuring sediment electrical conductances, a parameter that can be used to locate underwater areas of groundwater and contaminant upwelling. During towing, the probe does not roll or twist around its longitudinal axis by more than 10 deg, so that sensors, which have been fixed within the vehicle, can be oriented to look up, down, or sideways. In over 450 lin-km of underwater survey, only a single sediment probe has been irretrievably snagged on sunken rocks or other debris. Work in the Ottawa River near the Chalk River Laboratories has shown good agreement among point measurements of river sediment with continuous measurements using the moving probe

  11. Underwater inspection training in intense radiation field

    International Nuclear Information System (INIS)

    Taniguchi, Ryoichi

    2017-01-01

    Osaka Prefecture University has a large dose cobalt 60 gamma ray source of about 2 PBq, and is engaged in technological training and human resource development. It is assumed that the decommissioning underwater operation of Fukushima Daiichi Nuclear Power Station would be the focus. The university aims at acquisition of the basic of underwater inspection work under radiation environment that is useful for the above purpose, radiation measurement under water, basic training in image measurement, and aims as well to evaluate the damage of imaging equipment due to radiation, and master practical knowledge for the use of inspection equipment under a large dose. In particular, it is valuable to train in the observation of Cherenkov light emitted from a large dose cobalt radiation source in water using a high sensitivity camera. The measurement of radiation dose distribution in water had difficulty in remote measurement due to water shielding effect. Although it took much time before, the method using high sensitivity camera is easy to sequentially perform two-dimensional measurement, and its utility value is large. Its effect on the dose distribution measurement of irregularly shaped sources is great. The contents of training includes the following: radiation source imaging in water, use of a laser rangefinder in water, dose distribution measurement in water and Cherenkov light measurement, judgment of equipment damage due to irradiation, weak radiation measurement, and measurement and decontamination of surface contamination. (A.O.)

  12. Underwater noise from a wave energy converter

    DEFF Research Database (Denmark)

    Tougaard, Jakob

    A recent addition to the anthropogenic sources of underwater noise is offshore wave energy converters. Underwater noise was recorded from the Wavestar wave energy converter located at Hastholm, Denmark (57°7.73´N, 8°37.23´E). The Wavestar is a full-scale test and demonstration converter...... in full operation and start and stop of the converter. Median broad band (10 Hz – 20 kHz) sound pressure level (Leq) was 123 dB re. 1 Pa, irrespective of status of the wave energy converter (stopped, running or starting/stopping). The most pronounced peak in the third-octave spectrum was in the 160 Hz...... significant noise above ambient could be detected above the 250 Hz band. The absolute increase in noise above ambient was very small. L50 third-octave levels in the four bands with the converter running were thus only 1-2 dB above ambient L50 levels. The noise recorded 25 m from the wave energy converter...

  13. Hybrid Underwater Vehicle: ARV Design and Development

    Directory of Open Access Journals (Sweden)

    Zhigang DENG

    2014-02-01

    Full Text Available The development of SMU-I, a new autonomous & remotely-operated vehicle (ARV is described. Since it has both the characteristics of autonomous underwater vehicle (AUV and remote operated underwater vehicle (ROV, it is able to achieve precision fix station operation and manual timely intervention. In the paper the initial design of basic components, such as vehicle, propulsion, batteries etc. and the control design of motion are introduced and analyzed. ROV’s conventional cable is replaced by a fiber optic cable, which makes it available for high-bandwidth real-time video, data telemetry and high-quality teleoperation. Furthermore, with the aid of the manual real-time remote operation and ranging sonar, it also resolves the AUV’s conflicting issue, which can absolutely adapt the actual complex sea environment and satisfy the unknown mission need. The whole battery system is designed as two-battery banks, whose voltages and temperatures are monitored through CAN (controller area network bus to avoid battery fire and explosion. A fuzzy-PID controller is designed for its motion control, including depth control and direction control. The controller synthesizes the advantage of fuzzy control and PID control, utilizes the fuzzy rules to on-line tune the parameters of PID controller, and achieves a better control effect. Experiment results demonstrate to show the effectiveness of the test-bed.

  14. An explanatory model of underwater adaptation

    Directory of Open Access Journals (Sweden)

    Joaquín Colodro

    Full Text Available The underwater environment is an extreme environment that requires a process of human adaptation with specific psychophysiological demands to ensure survival and productive activity. From the standpoint of existing models of intelligence, personality and performance, in this explanatory study we have analyzed the contribution of individual differences in explaining the adaptation of military personnel in a stressful environment. Structural equation analysis was employed to verify a model representing the direct effects of psychological variables on individual adaptation to an adverse environment, and we have been able to confirm, during basic military diving courses, the structural relationships among these variables and their ability to predict a third of the variance of a criterion that has been studied very little to date. In this way, we have confirmed in a sample of professionals (N = 575 the direct relationship of emotional adjustment, conscientiousness and general mental ability with underwater adaptation, as well as the inverse relationship of emotional reactivity. These constructs are the psychological basis for working under water, contributing to an improved adaptation to this environment and promoting risk prevention and safety in diving activities.

  15. Modelling cavitating flow around underwater missiles

    Directory of Open Access Journals (Sweden)

    Fabien Petitpas

    2011-12-01

    Full Text Available The diffuse interface model of Saurel et al. (2008 is used for the computation of compressible cavitating flows around underwater missiles. Such systems use gas injection and natural cavitation to reduce drag effects. Consequently material interfaces appear separating liquid and gas. These interfaces may have a really complex dynamics such that only a few formulations are able to predict their evolution. Contrarily to front tracking or interface reconstruction method the interfaces are computed as diffused numerical zones, that are captured in a routinely manner, as is done usually with gas dynamics solvers for shocks and contact discontinuity. With the present approach, a single set of partial differential equations is solved everywhere, with a single numerical scheme. This leads to very efficient solvers. The algorithm derived in Saurel et al. (2009 is used to compute cavitation pockets around solid bodies. It is first validated against experiments done in cavitation tunnel at CNU. Then it is used to compute flows around high speed underwater systems (Shkval-like missile. Performance data are then computed showing method ability to predict forces acting on the system.

  16. The Investigation on Strain Strengthening Induced Martensitic Phase Transformation of Austenitic Stainless Steel: A Fundamental Research for the Quality Evaluation of Strain Strengthened Pressure Vessel

    Science.gov (United States)

    Li, Bo; Cai Ren, Fa; Tang, Xiao Ying

    2018-03-01

    The manufacture of pressure vessels with austenitic stainless steel strain strengthening technology has become an important technical means for the light weight of cryogenic pressure vessels. In the process of increasing the strength of austenitic stainless steel, strain can induce the martensitic phase transformation in austenite phase. There is a quantitative relationship between the transformation quantity of martensitic phase and the basic mechanical properties. Then, the martensitic phase variables can be obtained by means of detection, and the mechanical properties and safety performance are evaluated and calculated. Based on this, the quantitative relationship between strain hardening and deformation induced martensite phase content is studied in this paper, and the mechanism of deformation induced martensitic transformation of austenitic stainless steel is detailed.

  17. A 20 MW podded ship underwater electromagnetic signature - the alternative electric field; Signature electromagnetique sous-marine d'un paquebot de 20 MW a pods - le champ electrique alternatif

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, B.; Henocq, H.; Rannou, C. [Delegation Generale pour l' Armement, DET/GESMA, 75 - Paris (France); Albert, Th.; Harpin, D. [ALSTOM Marine (France); Bourguet, S.; Guerin, P. [Institut de Recherche en Electrotechnique et Electronique de Nantes Atlantique, 44 (France)

    2006-03-15

    Today, electric podded propulsion is used for many ships, cruise liners and Navy vessels.This propulsion uses high currents in extremely low frequencies (ELFE); currents flow through electrical network, equipment and pods. These alternative currents could generate important underwater electromagnetic field. GESMA has to quantify the level of this field and its impact on the signature of this kind of ship. Then, GESMA carried out electromagnetic measurements using a multi-sensors underwater and autonomous facility named AMI. It was placed on the route of a 20 MW podded ship, at one hundred meters depth from the surface. Especially, AMI observed an alternative radiated electric field... (authors)

  18. Underwater cladding with laser beam and plasma arc welding

    International Nuclear Information System (INIS)

    White, R.A.; Fusaro, R.; Jones, M.G.; Solomon, H.D.; Milian-Rodriguez, R.R.

    1997-01-01

    Two welding processes, plasma arc (transferred arc) (PTA) and laser beam, were investigated to apply cladding to austenitic stainless steels and Inconel 600. These processes have long been used to apply cladding layers , but the novel feature being reported here is that these cladding layers were applied underwater, with a water pressure equivalent to 24 m (80 ft). Being able to apply the cladding underwater is very important for many applications, including the construction of off-shore oil platforms and the repair of nuclear reactors. In the latter case, being able to weld underwater eliminates the need for draining the reactor and removing the fuel. Welding underwater in reactors presents numerous challenges, but the ability to weld without having to drain the reactor and remove the fuel provides a huge cost savings. Welding underwater in reactors must be done remotely, but because of the radioactive corrosion products and neutron activation of the steels, remote welding would also be required even if the reactor is drained and the fuel removed. In fact, without the shielding of the water, the remote welding required if the reactor is drained might be even more difficult than that required with underwater welds. Furthermore, as shall be shown, the underwater welds that the authors have made were of high quality and exhibit compressive rather than tensile residual stresses

  19. Underwater fiber-wireless communication with a passive front end

    Science.gov (United States)

    Xu, Jing; Sun, Bin; Lyu, Weichao; Kong, Meiwei; Sarwar, Rohail; Han, Jun; Zhang, Wei; Deng, Ning

    2017-11-01

    We propose and experimentally demonstrate a novel concept on underwater fiber-wireless (Fi-Wi) communication system with a fully passive wireless front end. A low-cost step-index (SI) plastic optical fiber (POF) together with a passive collimating lens at the front end composes the underwater Fi-Wi architecture. We have achieved a 1.71-Gb/s transmission at a mean BER of 4.97 × 10-3 (1.30 × 10-3 when using power loading) over a 50-m SI-POF and 2-m underwater wireless channel using orthogonal frequency division multiplexing (OFDM). Although the wireless part is very short, it actually plays a crucial role in practical underwater implementation, especially in deep sea. Compared with the wired solution (e.g. using a 52-m POF cable without the UWOC part), the proposed underwater Fi-Wi scheme can save optical wet-mate connectors that are sophisticated, very expensive and difficult to install in deep ocean. By combining high-capacity robust POF with the mobility and ubiquity of underwater wireless optical communication (UWOC), the proposed underwater Fi-Wi technology will find wide application in ocean exploration.

  20. Intelligent Navigation for a Solar Powered Unmanned Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Francisco García-Córdova

    2013-04-01

    Full Text Available In this paper, an intelligent navigation system for an unmanned underwater vehicle powered by renewable energy and designed for shadow water inspection in missions of a long duration is proposed. The system is composed of an underwater vehicle, which tows a surface vehicle. The surface vehicle is a small boat with photovoltaic panels, a methanol fuel cell and communication equipment, which provides energy and communication to the underwater vehicle. The underwater vehicle has sensors to monitor the underwater environment such as sidescan sonar and a video camera in a flexible configuration and sensors to measure the physical and chemical parameters of water quality on predefined paths for long distances. The underwater vehicle implements a biologically inspired neural architecture for autonomous intelligent navigation. Navigation is carried out by integrating a kinematic adaptive neuro-controller for trajectory tracking and an obstacle avoidance adaptive neuro- controller. The autonomous underwater vehicle is capable of operating during long periods of observation and monitoring. This autonomous vehicle is a good tool for observing large areas of sea, since it operates for long periods of time due to the contribution of renewable energy. It correlates all sensor data for time and geodetic position. This vehicle has been used for monitoring the Mar Menor lagoon.

  1. The influence of underwater turbulence on optical phase measurements

    Science.gov (United States)

    Redding, Brandon; Davis, Allen; Kirkendall, Clay; Dandridge, Anthony

    2016-05-01

    Emerging underwater optical imaging and sensing applications rely on phase-sensitive detection to provide added functionality and improved sensitivity. However, underwater turbulence introduces spatio-temporal variations in the refractive index of water which can degrade the performance of these systems. Although the influence of turbulence on traditional, non-interferometric imaging has been investigated, its influence on the optical phase remains poorly understood. Nonetheless, a thorough understanding of the spatio-temporal dynamics of the optical phase of light passing through underwater turbulence are crucial to the design of phase-sensitive imaging and sensing systems. To address this concern, we combined underwater imaging with high speed holography to provide a calibrated characterization of the effects of turbulence on the optical phase. By measuring the modulation transfer function of an underwater imaging system, we were able to calibrate varying levels of optical turbulence intensity using the Simple Underwater Imaging Model (SUIM). We then used high speed holography to measure the temporal dynamics of the optical phase of light passing through varying levels of turbulence. Using this method, we measured the variance in the amplitude and phase of the beam, the temporal correlation of the optical phase, and recorded the turbulence induced phase noise as a function of frequency. By bench marking the effects of varying levels of turbulence on the optical phase, this work provides a basis to evaluate the real-world potential of emerging underwater interferometric sensing modalities.

  2. Probabilistic atlas based labeling of the cerebral vessel tree

    Science.gov (United States)

    Van de Giessen, Martijn; Janssen, Jasper P.; Brouwer, Patrick A.; Reiber, Johan H. C.; Lelieveldt, Boudewijn P. F.; Dijkstra, Jouke

    2015-03-01

    Preoperative imaging of the cerebral vessel tree is essential for planning therapy on intracranial stenoses and aneurysms. Usually, a magnetic resonance angiography (MRA) or computed tomography angiography (CTA) is acquired from which the cerebral vessel tree is segmented. Accurate analysis is helped by the labeling of the cerebral vessels, but labeling is non-trivial due to anatomical topological variability and missing branches due to acquisition issues. In recent literature, labeling the cerebral vasculature around the Circle of Willis has mainly been approached as a graph-based problem. The most successful method, however, requires the definition of all possible permutations of missing vessels, which limits application to subsets of the tree and ignores spatial information about the vessel locations. This research aims to perform labeling using probabilistic atlases that model spatial vessel and label likelihoods. A cerebral vessel tree is aligned to a probabilistic atlas and subsequently each vessel is labeled by computing the maximum label likelihood per segment from label-specific atlases. The proposed method was validated on 25 segmented cerebral vessel trees. Labeling accuracies were close to 100% for large vessels, but dropped to 50-60% for small vessels that were only present in less than 50% of the set. With this work we showed that using solely spatial information of the vessel labels, vessel segments from stable vessels (>50% presence) were reliably classified. This spatial information will form the basis for a future labeling strategy with a very loose topological model.

  3. Underwater Leidenfrost nanochemistry for creation of size-tailored zinc peroxide cancer nanotherapeutics

    Science.gov (United States)

    Elbahri, Mady; Abdelaziz, Ramzy; Disci-Zayed, Duygu; Homaeigohar, Shahin; Sosna, Justyna; Adam, Dieter; Kienle, Lorenz; Dankwort, Torben; Abdelaziz, Moheb

    2017-05-01

    The dynamic underwater chemistry seen in nature is inspiring for the next generation of eco-friendly nanochemistry. In this context, green synthesis of size-tailored nanoparticles in a facile and scalable manner via a dynamic process is an interesting challenge. Simulating the volcano-induced dynamic chemistry of the deep ocean, here we demonstrate the Leidenfrost dynamic chemistry occurring in an underwater overheated confined zone as a new tool for customized creation of nanoclusters of zinc peroxide. The hydrodynamic nature of the phenomenon ensures eruption of the nanoclusters towards a much colder region, giving rise to growth of monodisperse, size-tailored nanoclusters. Such nanoparticles are investigated in terms of their cytotoxicity on suspension and adherent cells to prove their applicability as cancer nanotherapeutics. Our research can pave the way for employment of the dynamic green nanochemistry in facile, scalable fabrication of size-tailored nanoparticles for biomedical applications.

  4. Development and application of underwater robot vehicle for close inspection of spent fuels

    Energy Technology Data Exchange (ETDEWEB)

    Yun, J. S.; Park, B. S.; Song, T. G.; Kim, S. H.; Cho, M. W.; Ahn, S. H.; Lee, J. Y.; Oh, S. C.; Oh, W. J.; Shin, K. W.; Woo, D. H.; Kim, H. G.; Park, J. S

    1999-12-01

    The research and development efforts of the underwater robotic vehicle for inspection of spent fuels are focused on the development of an robotic vehicle which inspects spent fuels in the storage pool through remotely controlled actuation. For this purpose, a self balanced vehicle actuated by propellers is designed and fabricated, which consists of a radiation resistance camera, two illuminators, a pressure transducer and a manipulator. the algorithm for autonomous navigation is developed and its performance is tested at the swimming pool. The results of the underwater vehicle shows that the vehicle can easily navigate into the arbitrary directions while maintaining its balanced position. The camera provides a clear view of working environment by using the macro and zoom functions. The camera tilt device provides a wide field of view which is enough for monitoring the operation of manipulator. Also, the manipulator can pick up the dropped objects up to 4 kgf of weight. (author)

  5. State of the art report: Underwater examination techniques for spent nuclear fuels

    International Nuclear Information System (INIS)

    Chun, Yong Bum

    1997-06-01

    In these days, much efforts are being put to increase the final discharge burnup of PWR fuels. Therefore, the necessity of the inspection of irradiated nuclear fuels assembly during the the refueling outage is greatly increased to evaluate the safe operation and soundness of fuel assemblies in their next cycles in core, and apply the results for safe operation and effective core management. The necessity to evaluate the irradiation performance of indigenous nuclear fuels pushes the relative researchers to the development of on-site fuel inspection techniques and devices which can perform the underwater inspection and measurement of irradiated nuclear fuels during refueling outage. To ensure the technologies, the status of in situ underwater fuel inspection techniques and equipment were investigated and reviewed. Those information provides the fuel inspection capability to evaluate and certificate the performance and integrity of nuclear fuels which leads to the safe operation of NPP. (author). 49 refs., 52 figs

  6. Accuracy of Positioning Autonomous Biomimetic Underwater Vehicle Using Additional Measurement of Distances

    Directory of Open Access Journals (Sweden)

    Naus Krzysztof

    2016-12-01

    Full Text Available The article describes a study of problem of estimating the position coordinates of Autonomous Biomimetic Underwater Vehicle (ABUV using two methods: dead reckoning (DR and extended Kalman filter (EKF. In the first part of the paper, navigation system of ABUV is described and scientific problem with underwater positioning is formulated. The main part describes a way of estimating the position coordinates using DR and EKF and a numerical experiment involving motion of ABUV along the predetermined test distance. The final part of the paper contains a comparative statistical analysis of the results, carried out for assessing the accuracy of estimation of the position coordinates using DR and EKF methods. It presents the generalized conclusions from the research and the problems relating to the proper placement of the components of the system measuring distances.

  7. Underwater-manipulation system for measuring- and cutting tasks in dismantling decommissioned nuclear facilities. Final report

    International Nuclear Information System (INIS)

    Stegemann, D.; Reimche, W.; Hansch, M.; Spitzer, M.

    1995-01-01

    Not only manipulators are necessary for dismantling and inspection of structure parts in decomissioned nuclear facilities, but flexible underwater-vehicles. Free-diving underwater-vehicles for inspection and dismantling tasks are still not developed and tested. Aim of the project is the development of sensors and devices for the position determination and the depth regulation. For inspection tasks an ultrasonic measurement and dosimeter device shall be built up. A measurement device has been developed which evaluates the ultrasonic time of flight from a transmitter at the vehicle to several receivers, installed in the reactor pressure vessel. The depth regulation is based on a pressure sensor and the direct control of the thrusters. The ultrasonic measurements are realized by an adapted ultrasonic card, the γ-dosimetry with an ionization chamber and a pA-amplifier. An acoustic orientation system was built up, which measures very accurately with one transmitter mounted on the vehicle and four receivers. Problem occur by reflection from the walls of the basin. The depth regulation is working faultless. The ultrasonic device is preferably used for distance measurement. The radiation measurement device was tested and mounted in the vehicle. (orig./HP) [de

  8. Modelling, Design and Robust Control of a Remotely Operated Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Luis Govinda García-Valdovinos

    2014-01-01

    Full Text Available Underwater remotely operated vehicles (ROVs play an important role in a number of shallow and deep-water missions for marine science, oil and gas extraction, exploration and salvage. In these applications, the motions of the ROV are guided either by a human pilot on a surface support vessel through an umbilical cord providing power and telemetry, or by an automatic pilot. In the case of automatic control, ROV state feedback is provided by acoustic and inertial sensors and this state information, along with a controller strategy, is used to perform several tasks such as station-keeping and auto-immersion/heading, among others. In this paper, the modelling, design and control of the Kaxan ROV is presented: i The complete six degrees of freedom, non linear hydrodynamic model with its parameters, ii the Kaxan hardware/software architecture, iii numerical simulations in Matlab/Simulink platform of a model-free second order sliding mode control along with ocean currents as disturbances and thruster dynamics, iv a virtual environment to visualize the motion of the Kaxan ROV and v experimental results of a one degree of freedom underwater system.

  9. Reactor vessel sealing plug

    International Nuclear Information System (INIS)

    Dooley, R.A.

    1986-01-01

    This invention relates to an apparatus and method for sealing the cold leg nozzles of a nuclear reactor pressure vessel from a remote location during maintenance and inspection of associated steam generators and pumps while the pressure vessel and refueling canal are filled with water. The apparatus includes a sealing plug for mechanically sealing the cold leg nozzle from the inside of a reactor pressure vessel. The sealing plugs include a primary and a secondary O-ring. An installation tool is suspended within the reactor vessel and carries the sealing plug. The tool telescopes to insert the sealing plug within the cold leg nozzle, and to subsequently remove the plug. Hydraulic means are used to activate the sealing plug, and support means serve to suspend the installation tool within the reactor vessel during installation and removal of the sealing plug

  10. Containment vessel drain system

    Science.gov (United States)

    Harris, Scott G.

    2018-01-30

    A system for draining a containment vessel may include a drain inlet located in a lower portion of the containment vessel. The containment vessel may be at least partially filled with a liquid, and the drain inlet may be located below a surface of the liquid. The system may further comprise an inlet located in an upper portion of the containment vessel. The inlet may be configured to insert pressurized gas into the containment vessel to form a pressurized region above the surface of the liquid, and the pressurized region may operate to apply a surface pressure that forces the liquid into the drain inlet. Additionally, a fluid separation device may be operatively connected to the drain inlet. The fluid separation device may be configured to separate the liquid from the pressurized gas that enters the drain inlet after the surface of the liquid falls below the drain inlet.

  11. Autonomous docking control of visual-servo type underwater vehicle system aiming at underwater automatic charging

    International Nuclear Information System (INIS)

    Yanou, Akira; Ohnishi, Shota; Ishiyama, Shintaro; Minami, Mamoru

    2015-01-01

    A visual-servo type remotely operated vehicle (ROV) system with binocular wide-angle lens was developed to survey submarine resources, decontaminate radiation from mud in dam lake and so on. This paper explores the experiments on regulator performance and underwater docking of the robot system utilizing Genetic Algorithm (GA) for real-time recognition of the robot's relative position and posture through 3D marker. The visual servoing performances have been verified as follows; (1) The stability performances of the proposed regulator system have been evaluated by exerting abrupt distrubane force while the ROV is controlled by visual servoing. (2) The proposed system can track time-variant desired target position in x-axis (front-back direction of the robot). (3) The underwater docking can be completed by switching visual servoing and docking modes based on the error threshold, and by giving time-varying desired target position and orientation to the controller as a desired pose. (author)

  12. A Secure Communication Suite for Underwater Acoustic Sensor Networks

    Directory of Open Access Journals (Sweden)

    Angelica Lo Duca

    2012-11-01

    Full Text Available In this paper we describe a security suite for Underwater Acoustic Sensor Networks comprising both fixed and mobile nodes. The security suite is composed of a secure routing protocol and a set of cryptographic primitives aimed at protecting the confidentiality and the integrity of underwater communication while taking into account the unique characteristics and constraints of the acoustic channel. By means of experiments and simulations based on real data, we show that the suite is suitable for an underwater networking environment as it introduces limited, and sometimes negligible, communication and power consumption overhead.

  13. Application of YAG laser processing in underwater welding and cutting

    Energy Technology Data Exchange (ETDEWEB)

    Ohwaki, Katsura; Morita, Ichiro; Kojima, Toshio; Sato, Shuichi [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    2002-09-01

    The high-power YAG laser is a new fabrication tool. The laser torch is easy to combine with complex with complex mechanics because of beam delivery through optical fiber. A direct underwater laser welding technology has been developed and applied to the preservation, maintenance and removal of nuclear power plants. For subdividing or removing operations for retirement of plants, the laser cutting properties were confirmed to allow a maximum cutting thickness of 80 mm. For repairing inner surface of stainless steel tanks, an underwater laser welding system using a remote-controlled robot was developed and the high quality of underwater laser welding was confirmed. (author)

  14. WODA Technical Guidance on Underwater Sound from Dredging.

    Science.gov (United States)

    Thomsen, Frank; Borsani, Fabrizio; Clarke, Douglas; de Jong, Christ; de Wit, Pim; Goethals, Fredrik; Holtkamp, Martine; Martin, Elena San; Spadaro, Philip; van Raalte, Gerard; Victor, George Yesu Vedha; Jensen, Anders

    2016-01-01

    The World Organization of Dredging Associations (WODA) has identified underwater sound as an environmental issue that needs further consideration. A WODA Expert Group on Underwater Sound (WEGUS) prepared a guidance paper in 2013 on dredging sound, including a summary of potential impacts on aquatic biota and advice on underwater sound monitoring procedures. The paper follows a risk-based approach and provides guidance for standardization of acoustic terminology and methods for data collection and analysis. Furthermore, the literature on dredging-related sounds and the effects of dredging sounds on marine life is surveyed and guidance on the management of dredging-related sound risks is provided.

  15. Photogrammetry in maritime and underwater archaeology: two marble wrecks from Sicily

    Science.gov (United States)

    Balletti, C.; Beltrame, C.; Costa, E.; Guerra, F.; Vernier, P.

    2015-06-01

    Underwater survey, compared to land archaeology, needs some specific techniques, because the application of some active 3D sensor, such as laser scanner, is obviously impossible. The necessity to produce three-dimensional survey, offering the same accuracy of classical terrestrial laserscanning or photogrammetric methods, combined with the request of low costs and rapid solutions, led the researchers to test and apply oftentimes image-based techniques. In the last two years the Ca' Foscari University and University IUAV of Venice are conducting a research on the application of integrated techniques to support underwater metric documentation, comparing them to the manual traditional one. The gained experience (and confirmed by other recently published papers) shows that the actual multiimage digital photogrammetry is a good solution for the underwater archaeology. This approach is useful both from a metric and from a recording point of view, because it achieves high quality results, such as accurate 3D models or 2D representations, offering a complete documentation of underwater sites. But photogrammetry has to be supported by a topographical survey (to acquire ground control points - GCP) to georeference all the finds in the same reference system. This paper presents the integrated survey of two roman shipwrecks, approaching differently in the GCP's acquisition just for the different morphological characteristic of the sites. The wrecks' cargos are huge marble blocks, presenting differences in quantities, layout and depths. Those characteristics determine the choice of the topographic survey. The results of the survey are two 3D polygonal textured models of the sites, which can be easily used for different analyses and reconstructive hypothesis, opening new possibilities of documentation with both specialists and the wider public. Furthermore, 3D models are the geometric base for 2D orthophoto and cross section extraction. The paper will illustrate all the phases

  16. NCSX Vacuum Vessel Fabrication

    International Nuclear Information System (INIS)

    Viola ME; Brown T; Heitzenroeder P; Malinowski F; Reiersen W; Sutton L; Goranson P; Nelson B; Cole M; Manuel M; McCorkle D.

    2005-01-01

    The National Compact Stellarator Experiment (NCSX) is being constructed at the Princeton Plasma Physics Laboratory (PPPL) in conjunction with the Oak Ridge National Laboratory (ORNL). The goal of this experiment is to develop a device which has the steady state properties of a traditional stellarator along with the high performance characteristics of a tokamak. A key element of this device is its highly shaped Inconel 625 vacuum vessel. This paper describes the manufacturing of the vessel. The vessel is being fabricated by Major Tool and Machine, Inc. (MTM) in three identical 120 o vessel segments, corresponding to the three NCSX field periods, in order to accommodate assembly of the device. The port extensions are welded on, leak checked, cut off within 1-inch of the vessel surface at MTM and then reattached at PPPL, to accommodate assembly of the close-fitting modular coils that surround the vessel. The 120 o vessel segments are formed by welding two 60 o segments together. Each 60 o segment is fabricated by welding ten press-formed panels together over a collapsible welding fixture which is needed to precisely position the panels. The vessel is joined at assembly by welding via custom machined 8-inch (20.3 cm) wide spacer ''spool pieces''. The vessel must have a total leak rate less than 5 X 10 -6 t-l/s, magnetic permeability less than 1.02(micro), and its contours must be within 0.188-inch (4.76 mm). It is scheduled for completion in January 2006

  17. The NESTOR underwater neutrino telescope project

    Energy Technology Data Exchange (ETDEWEB)

    Rapidis, Petros A. [Institute of Nuclear Physics, National Center for Scientific Research ' Demokritos' , Athens 15310 (Greece)], E-mail: rapidis@inp.demokritos.gr

    2009-04-11

    The NESTOR collaboration is continuing its efforts towards deploying an underwater neutrino telescope. Further site studies (e.g. water light transmission measurements, sedimentation rates, etc.) are being carried out within the context of characterizing a site that may host the proposed KM3NeT infrastructure. In addition, following the successful deployment of a single floor of a NESTOR tower in 2003, five floors are now in the final stages of preparation. The use of these five floors in a form of a truncated tower together with four autonomous strings to be located some 300 m away from the tower is being contemplated. This arrangement, named NuBE (for Neutrino Burst Experiment), that may allow the detection neutrinos in coincidence with Gamma Ray Bursts, will be described.

  18. Transducers and arrays for underwater sound

    CERN Document Server

    Butler, John L

    2016-01-01

    This improved and updated second edition covers the theory, development, and design of electro-acoustic transducers for underwater applications. This highly regarded text discusses the basics of piezoelectric and magnetostrictive transducers that are currently being used as well as promising new designs. It presents the basic acoustics as well as the specific acoustics data needed in transducer design and evaluation. A broad range of designs of projectors and hydrophones are described in detail along with methods of modeling, evaluation, and measurement. Analysis of projector and hydrophone transducer arrays, including the effects of mutual radiation impedance and numerical models for elements and arrays, are also covered. The book includes new advances in transducer design and transducer materials and has been completely reorganized to be suitable for use as a textbook, as well as a reference or handbook. The new edition contains updates to the first edition, end-of-chapter exercises, and solutions to select...

  19. Collision Detection for Underwater ROV Manipulator Systems

    Directory of Open Access Journals (Sweden)

    Satja Sivčev

    2018-04-01

    Full Text Available Work-class ROVs equipped with robotic manipulators are extensively used for subsea intervention operations. Manipulators are teleoperated by human pilots relying on visual feedback from the worksite. Operating in a remote environment, with limited pilot perception and poor visibility, manipulator collisions which may cause significant damage are likely to happen. This paper presents a real-time collision detection algorithm for marine robotic manipulation. The proposed collision detection mechanism is developed, integrated into a commercial ROV manipulator control system, and successfully evaluated in simulations and experimental setup using a real industry standard underwater manipulator. The presented collision sensing solution has a potential to be a useful pilot assisting tool that can reduce the task load, operational time, and costs of subsea inspection, repair, and maintenance operations.

  20. The NESTOR underwater neutrino telescope project

    International Nuclear Information System (INIS)

    Rapidis, Petros A.

    2009-01-01

    The NESTOR collaboration is continuing its efforts towards deploying an underwater neutrino telescope. Further site studies (e.g. water light transmission measurements, sedimentation rates, etc.) are being carried out within the context of characterizing a site that may host the proposed KM3NeT infrastructure. In addition, following the successful deployment of a single floor of a NESTOR tower in 2003, five floors are now in the final stages of preparation. The use of these five floors in a form of a truncated tower together with four autonomous strings to be located some 300 m away from the tower is being contemplated. This arrangement, named NuBE (for Neutrino Burst Experiment), that may allow the detection neutrinos in coincidence with Gamma Ray Bursts, will be described.

  1. Underwater colorectal EMR: remodeling endoscopic mucosal resection.

    Science.gov (United States)

    Curcio, Gabriele; Granata, Antonino; Ligresti, Dario; Tarantino, Ilaria; Barresi, Luca; Liotta, Rosa; Traina, Mario

    2015-05-01

    Underwater EMR (UEMR) has been reported as a new technique for the removal of large sessile colorectal polyps without need for submucosal injection. To evaluate (1) outcomes of UEMR, (2) whether UEMR can be easily performed by an endoscopist skilled in traditional EMR without specific dedicated training in UEMR, and (3) whether EUS is required before UEMR. Prospective, observational study. Single, tertiary-care referral center. Underwater EMR. Complete resection and adverse events. A total of 72 consecutive patients underwent UEMR of 81 sessile colorectal polyps. EUS was performed before UEMR in 9 cases (11.1%) with a suspicious mucosal/vascular pattern. The mean polyp size was 18.7 mm (range 10-50 mm); the mean UEMR time was 11.8 minutes. Fifty-five polyps (68%) were removed en bloc, and 26 (32%) were removed with a piecemeal technique. Histopathology consisted of tubular adenomas (25.9%), tubulovillous adenomas (5%), adenomas with high-grade dysplasia (42%), serrated polyps (4.9%), carcinoma in situ (13.6%), and hyperplastic polyps (8.6%). Surveillance colonoscopy was scheduled at 3 months. Complete resection was successful in all patients. No adverse events or recurrence was recorded in any of the patients. Limited follow-up; single-center, uncontrolled study. Interventional endoscopists skilled in conventional EMR performed UEMR without specific dedicated training. EUS may not be required for lesions with no invasive features on high-definition narrow-band imaging. UEMR appears to be an effective and safe alternative to traditional EMR and could eventually improve the way in which we can effectively and safely treat colorectal lesions. Copyright © 2015 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

  2. Morphing hull implementation for unmanned underwater vehicles

    Science.gov (United States)

    Miller, Timothy F.; Gandhi, Farhan; Rufino, Russell J.

    2013-11-01

    There has been much interest and work in the area of morphing aircraft since the 1980s. Morphing could also potentially benefit unmanned underwater vehicles (UUVs). The current paper envisions a UUV with an interior pressure hull and a variable diameter outer flexible hull with fuel stored in the annulus between, and presents a mechanism to realize diameter change of the outer hull. The outer hull diameter of UUVs designed for very long endurance/range could be progressively reduced as fuel was consumed, thereby reducing drag and further increasing endurance and range capability. Diameter morphing could also be advantageous for compact storage of UUVs. A prototype is fabricated to represent an axial section of such a morphing diameter UUV. Diameter change is achieved using eight morphing trusses arranged equidistant around the circumference of the representative interior rigid hull. Each morphing truss has a lower rail (attached to the rigid hull) and an upper rail with V-linkages between, at either ends of the rail. Horizontal motion of the feet of the V-linkages (sliding in the lower rail) results in vertical motion of the upper rail which in turn produces diameter change of the outer hull. For the prototype built and tested, a 63% increase in outer diameter from 12.75″ to 20.75″ was achieved. The introduction of a stretched latex representative flexible skin around the outer rails increased actuation force requirement and led to a propensity for the wheel-in-track sliders in the morphing truss to bind. It is anticipated that this could be overcome with higher precision manufacturing. In addition to symmetric actuation of the morphing trusses resulting in diameter change, the paper also shows that with asymmetric actuation the hull cross-section shape can be changed (for example, from a circular section for underwater operation to a V-section for surface operations).

  3. Morphing hull implementation for unmanned underwater vehicles

    International Nuclear Information System (INIS)

    Miller, Timothy F; Gandhi, Farhan; Rufino, Russell J

    2013-01-01

    There has been much interest and work in the area of morphing aircraft since the 1980s. Morphing could also potentially benefit unmanned underwater vehicles (UUVs). The current paper envisions a UUV with an interior pressure hull and a variable diameter outer flexible hull with fuel stored in the annulus between, and presents a mechanism to realize diameter change of the outer hull. The outer hull diameter of UUVs designed for very long endurance/range could be progressively reduced as fuel was consumed, thereby reducing drag and further increasing endurance and range capability. Diameter morphing could also be advantageous for compact storage of UUVs. A prototype is fabricated to represent an axial section of such a morphing diameter UUV. Diameter change is achieved using eight morphing trusses arranged equidistant around the circumference of the representative interior rigid hull. Each morphing truss has a lower rail (attached to the rigid hull) and an upper rail with V-linkages between, at either ends of the rail. Horizontal motion of the feet of the V-linkages (sliding in the lower rail) results in vertical motion of the upper rail which in turn produces diameter change of the outer hull. For the prototype built and tested, a 63% increase in outer diameter from 12.75″ to 20.75″ was achieved. The introduction of a stretched latex representative flexible skin around the outer rails increased actuation force requirement and led to a propensity for the wheel-in-track sliders in the morphing truss to bind. It is anticipated that this could be overcome with higher precision manufacturing. In addition to symmetric actuation of the morphing trusses resulting in diameter change, the paper also shows that with asymmetric actuation the hull cross-section shape can be changed (for example, from a circular section for underwater operation to a V-section for surface operations). (paper)

  4. Radioactive waste processing vessel

    International Nuclear Information System (INIS)

    Hayashi, Masaru; Suzuki, Osamu; Ishizaki, Kanjiro.

    1987-01-01

    Purpose: To obtain a vessel of a reduced weight and with no external leaching of radioactive materials. Constitution: The vessel main body is constituted, for example, with light weight concretes or foamed concretes, particularly, foamed concretes containing fine closed bubbles in the inside. Then, layers having dense texture made of synthetic resin such as polystylene, vinylchloride resin, etc. or metal plate such as stainless plate are integrally disposed to the inner surface of the vessel main body. The cover member also has the same structure. (Sekiya, K.)

  5. Tempest in a vessel

    International Nuclear Information System (INIS)

    Barre, Bertrand

    2015-01-01

    As the ASN made some statements about anomalies of carbon content in the EPR vessel bottom and top, the author recalls and comments some technical issues to better understand the information published on this topic. He notably addresses the role of the vessel, briefly indicates its operating conditions, shape and structure, and mechanical components for the top, its material and mechanical properties, and test samples used to assess mechanical properties. He also comments the phenomenon of radio-induced embrittlement, the vessel manufacturing process, and evokes the applicable regulations. He quotes and comments statements made by the ASN and Areva which evoke further assessments of the concerned components

  6. Event localization in underwater wireless sensor networks using Monitoring Courses

    KAUST Repository

    Debont, Matthew John Robert; Jamshaid, Kamran; Shihada, Basem; Ho, Pin-Han

    2012-01-01

    We propose m-courses (Monitoring Courses), a novel solution to localize events in an underwater wireless sensor network. These networks consists of surface gateways and relay nodes. GPS can localize the position of surface gateways which can

  7. UTOFIA: an underwater time-of-flight image acquisition system

    Science.gov (United States)

    Driewer, Adrian; Abrosimov, Igor; Alexander, Jonathan; Benger, Marc; O'Farrell, Marion; Haugholt, Karl Henrik; Softley, Chris; Thielemann, Jens T.; Thorstensen, Jostein; Yates, Chris

    2017-10-01

    In this article the development of a newly designed Time-of-Flight (ToF) image sensor for underwater applications is described. The sensor is developed as part of the project UTOFIA (underwater time-of-flight image acquisition) funded by the EU within the Horizon 2020 framework. This project aims to develop a camera based on range gating that extends the visible range compared to conventional cameras by a factor of 2 to 3 and delivers real-time range information by means of a 3D video stream. The principle of underwater range gating as well as the concept of the image sensor are presented. Based on measurements on a test image sensor a pixel structure that suits best to the requirements has been selected. Within an extensive characterization underwater the capability of distance measurements in turbid environments is demonstrated.

  8. Trade-off Analysis of Underwater Acoustic Sensor Networks

    Science.gov (United States)

    Tuna, G.; Das, R.

    2017-09-01

    In the last couple of decades, Underwater Acoustic Sensor Networks (UASNs) were started to be used for various commercial and non-commercial purposes. However, in underwater environments, there are some specific inherent constraints, such as high bit error rate, variable and large propagation delay, limited bandwidth capacity, and short-range communications, which severely degrade the performance of UASNs and limit the lifetime of underwater sensor nodes as well. Therefore, proving reliability of UASN applications poses a challenge. In this study, we try to balance energy consumption of underwater acoustic sensor networks and minimize end-to-end delay using an efficient node placement strategy. Our simulation results reveal that if the number of hops is reduced, energy consumption can be reduced. However, this increases end-to-end delay. Hence, application-specific requirements must be taken into consideration when determining a strategy for node deployment.

  9. Localization of Energy Harvesting Empowered Underwater Optical Wireless Sensor Networks

    KAUST Repository

    Saeed, Nasir; Celik, Abdulkadir; Al-Naffouri, Tareq Y.; Alouini, Mohamed-Slim

    2017-01-01

    with insufficient battery, harvest the energy and starts communicating once it has sufficient energy storage. Network localization is carried out by measuring the RSSs of active nodes, which are modeled based on the underwater optical communication channel

  10. Multi-layer protective armour for underwater shock wave mitigation

    Directory of Open Access Journals (Sweden)

    Ahmed Hawass

    2015-12-01

    The strain gauge data and displacement sensors results showed that the multi-layer plates have higher level of underwater shock wave mitigation than the triple aluminum plates with strain and deflection of nearly 50%.

  11. Low-contrast underwater living fish recognition using PCANet

    Science.gov (United States)

    Sun, Xin; Yang, Jianping; Wang, Changgang; Dong, Junyu; Wang, Xinhua

    2018-04-01

    Quantitative and statistical analysis of ocean creatures is critical to ecological and environmental studies. And living fish recognition is one of the most essential requirements for fishery industry. However, light attenuation and scattering phenomenon are present in the underwater environment, which makes underwater images low-contrast and blurry. This paper tries to design a robust framework for accurate fish recognition. The framework introduces a two stage PCA Network to extract abstract features from fish images. On a real-world fish recognition dataset, we use a linear SVM classifier and set penalty coefficients to conquer data unbalanced issue. Feature visualization results show that our method can avoid the feature distortion in boundary regions of underwater image. Experiments results show that the PCA Network can extract discriminate features and achieve promising recognition accuracy. The framework improves the recognition accuracy of underwater living fishes and can be easily applied to marine fishery industry.

  12. Object detection from images obtained through underwater turbulence medium

    Science.gov (United States)

    Furhad, Md. Hasan; Tahtali, Murat; Lambert, Andrew

    2017-09-01

    Imaging through underwater experiences severe distortions due to random fluctuations of temperature and salinity in water, which produces underwater turbulence through diffraction limited blur. Lights reflecting from objects perturb and attenuate contrast, making the recognition of objects of interest difficult. Thus, the information available for detecting underwater objects of interest becomes a challenging task as they have inherent confusion among the background, foreground and other image properties. In this paper, a saliency-based approach is proposed to detect the objects acquired through an underwater turbulent medium. This approach has drawn attention among a wide range of computer vision applications, such as image retrieval, artificial intelligence, neuro-imaging and object detection. The image is first processed through a deblurring filter. Next, a saliency technique is used on the image for object detection. In this step, a saliency map that highlights the target regions is generated and then a graph-based model is proposed to extract these target regions for object detection.

  13. Network lifetime-aware data collection in Underwater Sensor ...

    Indian Academy of Sciences (India)

    Jalaja Janardanan Kartha

    2017-09-07

    Sep 7, 2017 ... existing models to assess their effectiveness and to investigate the trade-offs. Results show ... coverage drops below a predefined threshold and (vi) connectivity is .... Cost Clustering Protocol (MCCP), Distributed Underwater.

  14. Underwater Inherent Optical Properties Estimation Using a Depth Aided Deep Neural Network

    Directory of Open Access Journals (Sweden)

    Zhibin Yu

    2017-01-01

    Full Text Available Underwater inherent optical properties (IOPs are the fundamental clues to many research fields such as marine optics, marine biology, and underwater vision. Currently, beam transmissometers and optical sensors are considered as the ideal IOPs measuring methods. But these methods are inflexible and expensive to be deployed. To overcome this problem, we aim to develop a novel measuring method using only a single underwater image with the help of deep artificial neural network. The power of artificial neural network has been proved in image processing and computer vision fields with deep learning technology. However, image-based IOPs estimation is a quite different and challenging task. Unlike the traditional applications such as image classification or localization, IOP estimation looks at the transparency of the water between the camera and the target objects to estimate multiple optical properties simultaneously. In this paper, we propose a novel Depth Aided (DA deep neural network structure for IOPs estimation based on a single RGB image that is even noisy. The imaging depth information is considered as an aided input to help our model make better decision.

  15. Underwater Topography Detection in Coastal Areas Using Fully Polarimetric SAR Data

    Directory of Open Access Journals (Sweden)

    Xiaolin Bian

    2017-06-01

    Full Text Available Fully polarimetric synthetic aperture radar (SAR can provide detailed information on scattering mechanisms that could enable the target or structure to be identified. This paper presents a method to detect underwater topography in coastal areas using high resolution fully polarimetric SAR data, while less prior information is required. The method is based on the shoaling and refraction of long surface gravity waves as they propagate shoreward. First, the surface scattering component is obtained by polarization decomposition. Then, wave fields are retrieved from the two-dimensional (2D spectra by the Fast Fourier Transformation (FFT. Finally, shallow water depths are estimated from the dispersion relation. Applicability and effectiveness of the proposed methodology are tested by using C-band fine quad-polarization mode RADARSAT-2 SAR data over the near-shore area of the Hainan province, China. By comparing with the values from an official electronic navigational chart (ENC, the estimated water depths are in good agreement with them. The average relative error of the detected results from the scattering mechanisms based method and single polarization SAR data are 9.73% and 11.53% respectively. The validation results indicate that the scattering mechanisms based methodology is more effective than only using the single polarization SAR data for underwater topography detection, and will inspire further research on underwater topography detection with fully polarimetric SAR data.

  16. Development of measuring and control systems for underwater cutting of radioactive components

    International Nuclear Information System (INIS)

    Drews, P.; Fuchs, K.

    1990-01-01

    Shutdown and dismantling of nuclear power plants requires special techniques to decommission the radioactive components involved. For reasons of safety, decommissioning of components under water can be advantageous because of the radioactive shielding effect of water. In this project, research activities and developmental works focused on the realization of different sensor systems and their adaptation to cutting tasks. A new image-processing system has been developed in addition to the use of a modified underwater TV camera for optical cutting process control (plasma and abrasive wheel cutting). For control of process parameters, different inductive, ultrasonic and optical sensors have been modified and tested. The investigations performed are aimed at assuring high-quality underwater cutting with the help of sensor systems specially adapted to cutting tasks, with special signal procession and evaluation through microcomputer control. It is important that special attention be paid to the reduction of interferences in image pick-up and procession. The measuring system has been designed and realized according to the consideration of the demands for underwater cutting processes. The reliability of the system was tested in conjunction with a four-axes handling system

  17. Underwater Inherent Optical Properties Estimation Using a Depth Aided Deep Neural Network.

    Science.gov (United States)

    Yu, Zhibin; Wang, Yubo; Zheng, Bing; Zheng, Haiyong; Wang, Nan; Gu, Zhaorui

    2017-01-01

    Underwater inherent optical properties (IOPs) are the fundamental clues to many research fields such as marine optics, marine biology, and underwater vision. Currently, beam transmissometers and optical sensors are considered as the ideal IOPs measuring methods. But these methods are inflexible and expensive to be deployed. To overcome this problem, we aim to develop a novel measuring method using only a single underwater image with the help of deep artificial neural network. The power of artificial neural network has been proved in image processing and computer vision fields with deep learning technology. However, image-based IOPs estimation is a quite different and challenging task. Unlike the traditional applications such as image classification or localization, IOP estimation looks at the transparency of the water between the camera and the target objects to estimate multiple optical properties simultaneously. In this paper, we propose a novel Depth Aided (DA) deep neural network structure for IOPs estimation based on a single RGB image that is even noisy. The imaging depth information is considered as an aided input to help our model make better decision.

  18. Measurement and analysis of self-noise in hybrid-driven underwater gliders

    Directory of Open Access Journals (Sweden)

    LIU Lu

    2017-08-01

    Full Text Available The Hybrid-driven Underwater Glider (HUG is a new type of submersible vehicle which combines the functions of traditional Autonomous Underwater Vehicles(AUVand Autonomous Underwater Gliders(AUG. In order to study its noise source distribution and basic self-noise characteristics, a self-noise acquisition system based on the HUG was designed and developed, and a noise analysis test carried out in a free-field pool. In August 2016, the sea trial of the Petrel II glider was conducted in the South China Sea, with observation data at a depth range of 1 000 m as the research object. The self-noise data of the glider platform under different working conditions was obtained through the step-by-step operation method. The experimental analysis and results show that the self-noise acquisition system is stable. The contribution of mechanical noise to self-noise is greatest when the glider works in the gliding mode, while the self-noise band above 500 Hz is closely related to the work of the buoyancy adjustment unit, and peaks at 1 kHz. According to the analysis of the basic characteristics of self-noise, this provides some guidance for the implementation of vibration and noise reduction.

  19. Influence of range-gated intensifiers on underwater imaging system SNR

    Science.gov (United States)

    Wang, Xia; Hu, Ling; Zhi, Qiang; Chen, Zhen-yue; Jin, Wei-qi

    2013-08-01

    Range-gated technology has been a hot research field in recent years due to its high effective back scattering eliminating. As a result, it can enhance the contrast between a target and its background and extent the working distance of the imaging system. The underwater imaging system is required to have the ability to image in low light level conditions, as well as the ability to eliminate the back scattering effect, which means that the receiver has to be high-speed external trigger function, high resolution, high sensitivity, low noise, higher gain dynamic range. When it comes to an intensifier, the noise characteristics directly restrict the observation effect and range of the imaging system. The background noise may decrease the image contrast and sharpness, even covering the signal making it impossible to recognize the target. So it is quite important to investigate the noise characteristics of intensifiers. SNR is an important parameter reflecting the noise features of a system. Through the use of underwater laser range-gated imaging prediction model, and according to the linear SNR system theory, the gated imaging noise performance of the present market adopted super second generation and generation Ⅲ intensifiers were theoretically analyzed. Based on the active laser underwater range-gated imaging model, the effect to the system by gated intensifiers and the relationship between the system SNR and MTF were studied. Through theoretical and simulation analysis to the image intensifier background noise and SNR, the different influence on system SNR by super second generation and generation Ⅲ ICCD was obtained. Range-gated system SNR formula was put forward, and compared the different effect influence on the system by using two kind of ICCDs was compared. According to the matlab simulation, a detailed analysis was carried out theoretically. All the work in this paper lays a theoretical foundation to further eliminating back scattering effect, improving

  20. The alkaline aluminium/hydrogen peroxide power source in the Hugin II unmanned underwater vehicle

    Science.gov (United States)

    Hasvold, Øistein; Johansen, Kjell Håvard; Mollestad, Ole; Forseth, Sissel; Størkersen, Nils

    In 1993, The Norwegian Defence Research Establishment (FFI) demonstrated AUV-Demo, an unmanned (untethered) underwater vehicle (UUV), powered by a magnesium/dissolved oxygen seawater battery (SWB). This technology showed that an underwater range of at least 1000 nautical miles at a speed of 4 knots was possible, but also that the maximum hotel load this battery system could support was very limited. Most applications for UUV technology need more power over a shorter period of time. Seabed mapping using a multibeam echo sounder mounted on an UUV was identified as a viable application and the Hugin project was started in 1995 in cooperation with Norwegian industry. For this application, an endurance of 36 h at 4 knots was required. Development of the UUV hull and electronics system resulted in the UUV Hugin I. It carries a Ni/Cd battery of 3 kW h, allowing up to 6 h under-water endurance. In parallel, we developed a battery based on a combination of alkaline Al/air and SWB technology, using a circulating alkaline electrolyte, aluminium anodes and maintaining the oxidant concentration in the electrolyte by continuously adding hydrogen peroxide (HP) to the electrolyte. This concept resulted in a safe battery, working at ambient pressure (balanced) and with sufficient power and energy density to allow the UUV Hugin II to make a number of successive dives, each of up to 36 h duration and with only 1 h deck time between dives for HP refill and electrolyte exchange. After 100 h, an exchange of anodes takes place. The power source consists of a four-cell Al/HP battery, a DC/DC converter delivering 600 W at 30 V, circulation and dosing pumps and a battery control unit. Hugin II is now in routine use by the Norwegian Underwater Intervention AS (NUI) which operates the UUV for high-precision seabed mapping down to a water depth of 600 m.

  1. Multi-layer protective armour for underwater shock wave mitigation

    OpenAIRE

    Ahmed Hawass; Hosam Mostafa; Ahmed Elbeih

    2015-01-01

    The effect of underwater shock wave on different target plates has been studied. An underwater shock wave generator (shock tube) was used to study the interactions between water and different constructed targets which act as shock wave mitigation. Target plates, composed of sandwich of two aluminum sheets with rubber and foam in between, were prepared and studied. For comparison, the target plates composed of triple aluminum sheets were tested. The study includes the testing of the selected p...

  2. FILMING UNDERWATER IN 3D RESPECTING STEREOGRAPHIC RULES

    OpenAIRE

    R. Rinaldi; H. Hordosch

    2015-01-01

    After an experimental phase of many years, 3D filming is now effective and successful. Improvements are still possible, but the film industry achieved memorable success on 3D movie’s box offices due to the overall quality of its products. Special environments such as space ("Gravity") and the underwater realm look perfect to be reproduced in 3D. "Filming in space" was possible in "Gravity" using special effects and computer graphic. The underwater realm is still difficult to be handled. Under...

  3. Remote Underwater Characterization System - Innovative Technology Summary Report

    International Nuclear Information System (INIS)

    Willis, Walter David

    1999-01-01

    Characterization and inspection of water-cooled and moderated nuclear reactors and fuel storage pools requires equipment capable of operating underwater. Similarly, the deactivation and decommissioning of older nuclear facilities often requires the facility owner to accurately characterize underwater structures and equipment which may have been sitting idle for years. The underwater characterization equipment is often required to operate at depths exceeding 20 ft (6.1 m) and in relatively confined or congested spaces. The typical baseline approach has been the use of radiation detectors and underwater cameras mounted on long poles, or stationary cameras with pan and tilt features mounted on the sides of the underwater facility. There is a perceived need for an inexpensive, more mobile method of performing close-up inspection and radiation measurements in confined spaces underwater. The Remote Underwater Characterization System (RUCS) is a small, remotely operated submersible vehicle intended to serve multiple purposes in underwater nuclear operations. It is based on the commercially-available ''Scallop'' vehicle, but has been modified by Department of Energy's Robotics Technology Development Program to add auto-depth control, and vehicle orientation and depth monitoring at the operator control panel. The RUCS is designed to provide visual and gamma radiation characterization, even in confined or limited access areas. It was demonstrated in August 1998 at Idaho National Engineering and environmental Laboratory (INEEL) as part of the INEEL Large Scale Demonstration and Deployment Project. During the demonstration it was compared in a ''head-to-head'' fashion with the baseline characterization technology. This paper summarizes the results of the demonstration and lessons learned; comparing and contrasting both technologies in the areas of cost, visual characterization, radiological characterization, and overall operations

  4. Strong tracking adaptive Kalman filters for underwater vehicle dead reckoning

    Institute of Scientific and Technical Information of China (English)

    XIAO Kun; FANG Shao-ji; PANG Yong-jie

    2007-01-01

    To improve underwater vehicle dead reckoning, a developed strong tracking adaptive kalman filter is proposed. The filter is improved with an additional adaptive factor and an estimator of measurement noise covariance. Since the magnitude of fading factor is changed adaptively, the tracking ability of the filter is still enhanced in low velocity condition of underwater vehicles. The results of simulation tests prove the presented filter effective.

  5. On the Performance of the Underwater Acoustic Sensor Networks

    Science.gov (United States)

    2015-05-01

    performance of UWSN. 5.1 Hardware and Software Details 5.1.1 Equipment Our experimental model consisted of an indoor swimming pool , two pairs...UWSN has many constraints mainly due to limited capacity, propagation loss, as well as power limitation since in underwater environment solar energy ...since in underwater environment solar energy cannot be used to recharge batteries. In our approach, we estimate the number of operating receivers

  6. The Theseus Autonomous Underwater Vehicle: A Canadian Success Story

    Science.gov (United States)

    1997-04-01

    P502414.PDF [Page: 1 of 9] P502414.PDF [Page: 2 of 9] P502414.PDF [Page: 3 of 9] The Theseus Autonomous Underwater Vehicle A Canadian Success Story...autonomous underwater vehicle, named Theseus , for laying optical fiber cables in ice- covered waters. In trials and missions conducted in 1996, this...stations. An acoustic telemetry system enables communication with Theseus from surface stations, and an optical telemetry system is used for system

  7. Monterey Bay ambient noise profiles using underwater gliders

    OpenAIRE

    Chandrayadula, Tarun K.; Miller, Chris W.; Joseph, John

    2013-01-01

    The article of record as published may be found at http://dx.doi.org/10.1121/1.4799131 In 2012, during two separate week-long deployments, underwater gliders outfitted with external hydrophones profiled the upper 100-200 m of the Monterey Bay. The environment contained various noises made by marine mammals, ships, winds, and earthquakes. Unlike hydrophone receivers moored to a fixed location, moving gliders measure noise variability across a wide terrain. However, underwater mobile s...

  8. Cheboygan Vessel Base

    Data.gov (United States)

    Federal Laboratory Consortium — Cheboygan Vessel Base (CVB), located in Cheboygan, Michigan, is a field station of the USGS Great Lakes Science Center (GLSC). CVB was established by congressional...

  9. High Performance Marine Vessels

    CERN Document Server

    Yun, Liang

    2012-01-01

    High Performance Marine Vessels (HPMVs) range from the Fast Ferries to the latest high speed Navy Craft, including competition power boats and hydroplanes, hydrofoils, hovercraft, catamarans and other multi-hull craft. High Performance Marine Vessels covers the main concepts of HPMVs and discusses historical background, design features, services that have been successful and not so successful, and some sample data of the range of HPMVs to date. Included is a comparison of all HPMVs craft and the differences between them and descriptions of performance (hydrodynamics and aerodynamics). Readers will find a comprehensive overview of the design, development and building of HPMVs. In summary, this book: Focuses on technology at the aero-marine interface Covers the full range of high performance marine vessel concepts Explains the historical development of various HPMVs Discusses ferries, racing and pleasure craft, as well as utility and military missions High Performance Marine Vessels is an ideal book for student...

  10. 2011 Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  11. 2011 Fishing Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  12. Pressurized Vessel Slurry Pumping

    International Nuclear Information System (INIS)

    Pound, C.R.

    2001-01-01

    This report summarizes testing of an alternate ''pressurized vessel slurry pumping'' apparatus. The principle is similar to rural domestic water systems and ''acid eggs'' used in chemical laboratories in that material is extruded by displacement with compressed air

  13. 2013 Tanker Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  14. Maury Journals - US Vessels

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — U.S. vessels observations, after the 1853 Brussels Conference that set International Maritime Standards, modeled after Maury Marine Standard Observations.

  15. Coastal Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains catch (landed catch) and effort for fishing trips made by vessels that have been issued a Federal permit for the Gulf of Mexico reef fish,...

  16. Reactor pressure vessel support

    International Nuclear Information System (INIS)

    Butti, J.P.

    1977-01-01

    A link and pin support system provides the primary vertical and lateral support for a nuclear reactor pressure vessel without restricting thermally induced radial and vertical expansion and contraction. (Auth.)

  17. 2013 Cargo Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  18. 2013 Fishing Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  19. 2013 Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  20. Ocean Station Vessel

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Ocean Station Vessels (OSV) or Weather Ships captured atmospheric conditions while being stationed continuously in a single location. While While most of the...

  1. Vessel Sewage Discharges

    Science.gov (United States)

    Vessel sewage discharges are regulated under Section 312 of the Clean Water Act, which is jointly implemented by the EPA and Coast Guard. This homepage links to information on marine sanitation devices and no discharge zones.

  2. Interstitial Cells of Blood Vessels

    Directory of Open Access Journals (Sweden)

    Vladimír Pucovský

    2010-01-01

    Full Text Available Blood vessels are made up of several distinct cell types. Although it was originally thought that the tunica media of blood vessels was composed of a homogeneous population of fully differentiated smooth muscle cells, more recent data suggest the existence of multiple smooth muscle cell subpopulations in the vascular wall. One of the cell types contributing to this heterogeneity is the novel, irregularly shaped, noncontractile cell with thin processes, termed interstitial cell, found in the tunica media of both veins and arteries. While the principal role of interstitial cells in veins seems to be pacemaking, the role of arterial interstitial cells is less clear. This review summarises the knowledge of the functional and structural properties of vascular interstitial cells accumulated so far, offers hypotheses on their physiological role, and proposes directions for future research.

  3. Cardiovascular response during submaximal underwater treadmill exercise in stroke patients.

    Science.gov (United States)

    Yoo, Jeehyun; Lim, Kil-Byung; Lee, Hong-Jae; Kwon, Yong-Geol

    2014-10-01

    To evaluate the cardiovascular response during head-out water immersion, underwater treadmill gait, and land treadmill gait in stroke patients. Ten stroke patients were recruited for underwater and land treadmill gait sessions. Each session was 40 minutes long; 5 minutes for standing rest on land, 5 minutes for standing rest in water or on treadmill, 20 minutes for treadmill walking in water or on land, 5 minutes for standing rest in water or on treadmill, and 5 minutes for standing rest on land. Blood pressure (BP) and heart rate (HR) were measured during each session. In order to estimate the cardiovascular workload and myocardial oxygen demand, the rate pressure product (RPP) value was calculated by multiplying systolic BP (SBP) by HR. SBP, DBP, mean BP (mBP), and RPP decreased significantly after water immersion, but HR was unchanged. During underwater and land treadmill gait, SBP, mBP, DBP, RPP, and HR increased. However, the mean maximum increases in BP, HR and RPP of underwater treadmill walking were significantly lower than that of land treadmill walking. Stroke patients showed different cardiovascular responses during water immersion and underwater gait as opposed to standing and treadmill-walking on land. Water immersion and aquatic treadmill gait may reduce the workload of the cardiovascular system. This study suggested that underwater treadmill may be a safe and useful option for cardiovascular fitness and early ambulation in stroke rehabilitation.

  4. Reactor pressure vessel design

    International Nuclear Information System (INIS)

    Foehl, J.

    1998-01-01

    As a result of the popularity of the Agencies report 'Neutron Irradiation Embrittlement of Reactor Pressure Vessel Steels' of 1975, it was decided that another report on this broad subject would be of use. In this report, background and contemporary views on specially identified areas of the subject are considered as self-contained chapters, written by experts. In chapter 2, the general principles of reactor pressure vessel design are elaborated. Crack and fracture initiation and propagation are treated in some detail

  5. Graywater Discharges from Vessels

    Science.gov (United States)

    2011-11-01

    metals (e.g., cadmium, chromium, lead, copper , zinc, silver, nickel, and mercury), solids, and nutrients (USEPA, 2008b; USEPA 2010). Wastewater from... flotation ), and disinfection (using ultraviolet light) as compared to traditional Type II MSDs that use either simple maceration and chlorination, or...Coliform Naval Vessels Oceanographic Vessels Small Cruise Ships 25a Vendor 2 Hamann AG Biological Treatment with Dissolved Air Flotation and

  6. LANL Robotic Vessel Scanning

    Energy Technology Data Exchange (ETDEWEB)

    Webber, Nels W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-25

    Los Alamos National Laboratory in J-1 DARHT Operations Group uses 6ft spherical vessels to contain hazardous materials produced in a hydrodynamic experiment. These contaminated vessels must be analyzed by means of a worker entering the vessel to locate, measure, and document every penetration mark on the vessel. If the worker can be replaced by a highly automated robotic system with a high precision scanner, it will eliminate the risks to the worker and provide management with an accurate 3D model of the vessel presenting the existing damage with the flexibility to manipulate the model for better and more in-depth assessment.The project was successful in meeting the primary goal of installing an automated system which scanned a 6ft vessel with an elapsed time of 45 minutes. This robotic system reduces the total time for the original scope of work by 75 minutes and results in excellent data accumulation and transmission to the 3D model imaging program.

  7. A mission executor for an autonomous underwater vehicle

    Science.gov (United States)

    Lee, Yuh-Jeng; Wilkinson, Paul

    1991-01-01

    The Naval Postgraduate School has been conducting research into the design and testing of an Autonomous Underwater Vehicle (AUV). One facet of this research is to incrementally design a software architecture and implement it in an advanced testbed, the AUV II. As part of the high level architecture, a Mission Executor is being constructed using CLIPS (C Language Integrated Production System) version 5.0. The Mission Executor is an expert system designed to oversee progress from the AUV launch point to a goal area and back to the origin. It is expected that the executor will make informed decisions about the mission, taking into account the navigational path, the vehicle subsystem health, and the sea environment, as well as the specific mission profile which is downloaded from an offboard mission planner. Heuristics for maneuvering, avoidance of uncharted obstacles, waypoint navigation, and reaction to emergencies (essentially the expert knowledge of a submarine captain) are required. Many of the vehicle subsystems are modeled as objects using the CLIPS Object Oriented Language (COOL) embedded in CLIPS 5.0. Also, truth maintenance is applied to the knowledge base to keep configurations updated.

  8. Jellyfish Identification Software for Underwater Laser Cameras (JTRACK

    Directory of Open Access Journals (Sweden)

    Patrizio Mariani

    2018-02-01

    Full Text Available Jellyfish can form erratic blooms in response to seasonal and irregular changes in environmental conditions with often large, transient effects on local ecosystem structure as well as effects on several sectors of the marine and maritime economy. Early warning systems able to detect conditions for jelly fish proliferation can enable management responses to mitigate such effects providing benefit to local ecosystems and economies. We propose here the creation of a research team in response to the EU call for proposal under the European Maritime and Fisheries Fund called “Blue Labs: innovative solutions for maritime challenges”. The project will establish a BLUELAB team with a strong cross-sectorial component that will benefit of the expertise of researchers in IT and Marine Biology, Computer Vision and embedded systems, which will work in collaboration with Industry and Policy maker to develop an early warning system using a new underwater imaging system based on Time of Flight Laser cameras. The camera will be combined to machine learning algorithm allowing autonomous early detection of jellyfish species (e.g. polyp, ephyra and planula stages. The team will develop the system and the companion software and will demonstrate its applications in real case conditions.

  9. FFTF and CRBRP reactor vessels

    International Nuclear Information System (INIS)

    Morgan, R.E.

    1977-01-01

    The Fast Flux Test Facility (FFTF) reactor vessel and the Clinch River Breeder Reactor Plant (CRBRP) reactor vessel each serve to enclose a fast spectrum reactor core, contain the sodium coolant, and provide support and positioning for the closure head and internal structure. Each vessel is located in its reactor cavity and is protected by a guard vessel which would ensure continued decay heat removal capability should a major system leak develop. Although the two plants have significantly different thermal power ratings, 400 megawatts for FFTF and 975 megawatts for CRBRP, the two reactor vessels are comparable in size, the CRBRP vessel being approximately 28% longer than the FFTF vessel. The FFTF vessel diameter was controlled by the space required for the three individual In-Vessel Handling Machines and Instrument Trees. Utilization of the triple rotating plug scheme for CRBRP refueling enables packaging of the larger CRBRP core in a vessel the same diameter as the FFTF vessel

  10. Twenty-fifth water reactor safety information meeting: Proceedings. Volume 1: Plenary sessions; Pressure vessel research; BWR strainer blockage and other generic safety issues; Environmentally assisted degradation of LWR components; Update on severe accident code improvements and applications

    International Nuclear Information System (INIS)

    Monteleone, S.

    1998-03-01

    This three-volume report contains papers presented at the conference. The papers are printed in the order of their presentation in each session and describe progress and results of programs in nuclear safety research conducted in this country and abroad. Foreign participation in the meeting included papers presented by researchers from France, Japan, Norway, and Russia. The titles of the papers and the names of the authors have been updated and may differ from those that appeared in the final program of the meeting. This volume contains the following information: (1) plenary sessions; (2) pressure vessel research; (3) BWR strainer blockage and other generic safety issues; (4) environmentally assisted degradation of LWR components; and (5) update on severe accident code improvements and applications. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database

  11. Twenty-fifth water reactor safety information meeting: Proceedings. Volume 1: Plenary sessions; Pressure vessel research; BWR strainer blockage and other generic safety issues; Environmentally assisted degradation of LWR components; Update on severe accident code improvements and applications

    Energy Technology Data Exchange (ETDEWEB)

    Monteleone, S. [comp.] [Brookhaven National Lab., Upton, NY (United States)

    1998-03-01

    This three-volume report contains papers presented at the conference. The papers are printed in the order of their presentation in each session and describe progress and results of programs in nuclear safety research conducted in this country and abroad. Foreign participation in the meeting included papers presented by researchers from France, Japan, Norway, and Russia. The titles of the papers and the names of the authors have been updated and may differ from those that appeared in the final program of the meeting. This volume contains the following information: (1) plenary sessions; (2) pressure vessel research; (3) BWR strainer blockage and other generic safety issues; (4) environmentally assisted degradation of LWR components; and (5) update on severe accident code improvements and applications. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  12. Sexual harassment within the marine sciences and the ethical dilemmas of collaboration: a case study in the education and reportino methods available to scientists, students, and staff on board a federal research vessel

    Science.gov (United States)

    Ohern, J.

    2016-02-01

    Within the Science, technology, engineering, and math (STEM) disciplines, a disparity between male and female involvement persists on the order of about 3:1. While roughly 40% of men with STEM degrees go on to pursue STEM jobs, just 26% of women with STEM degrees hold jobs within the STEM field. There are a number of contributing factors to these disparities, but one pernicious factor is the issue of sexual harassment and discrimination. For the marine sciences this is an especially concerning issue because our field research frequently takes place hundreds of miles offshore. Despite education and policy initiatives, sexual harassment pervades many research vessels and is often never addressed, discouraging female involvement and limiting the opportunities available to women. Ethical dilemmas develop when administrators do not want to risk limited field schedules and funding while investigations are conducted and harassment issues resolved. Additionally, scientists and staff often collaborate between institutions, benefitting science but blurring the lines of responsibility. In one such case, administrators within a federal research office declined to report sexual harassment taking place between contracted crew members on their research vessel. The lengthy review process and lack of culpability discourages reporting of sexual harassment and allows problematic situations to occur. This case study reviews the reporting mechanisms currently in place, the barriers to reporting, and the proposed methods for more effectively resolving discriminatory workplaces. Collaboration within marine science is an absolute necessity, and our research benefits from diverse working groups. As marine scientists we have an ethical responsibility to ensure safe working environments for both the scientists and the staff who make our research possible.

  13. Underwater Animal Monitoring Magnetic Sensor System

    KAUST Repository

    Kaidarova, Altynay

    2017-10-01

    Obtaining new insights into the behavior of free-living marine organisms is fundamental for conservation efforts and anticipating the impact of climate change on marine ecosystems. Despite the recent advances in biotelemetry, collecting physiological and behavioral parameters of underwater free-living animals remains technically challenging. In this thesis, we develop the first magnetic underwater animal monitoring system that utilizes Tunnel magnetoresistance (TMR) sensors, the most sensitive solid-state sensors today, coupled with flexible magnetic composites. The TMR sensors are composed of CoFeB free layers and MgO tunnel barriers, patterned using standard optical lithography and ion milling procedures. The short and long-term stability of the TMR sensors has been studied using statistical and Allan deviation analysis. Instrumentation noise has been reduced using optimized electrical interconnection schemes. We also develop flexible NdFeB-PDMS composite magnets optimized for applications in corrosive marine environments, and which can be attached to marine animals. The magnetic and mechanical properties are studied for different NdFeB powder concentrations and the performance of the magnetic composites for different exposure times to sea water is systematically investigated. Without protective layer, the composite magnets loose more than 50% of their magnetization after 51 days in seawater. The durability of the composite magnets can be considerably improved by using polymer coatings which are protecting the composite magnet, whereby Parylene C is found to be the most effective solution, providing simultaneously corrosion resistance, flexibility, and enhanced biocompatibility. A Parylene C film of 2μm thickness provides the sufficient protection of the magnetic composite in corrosive aqueous environments for more than 70 days. For the high level performance of the system, the theoretically optimal position of the composite magnets with respect to the sensing

  14. BY FRUSTUM CONFINING VESSEL

    Directory of Open Access Journals (Sweden)

    Javad Khazaei

    2016-09-01

    Full Text Available Helical piles are environmentally friendly and economical deep foundations that, due to environmental considerations, are excellent additions to a variety of deep foundation alternatives available to the practitioner. Helical piles performance depends on soil properties, the pile geometry and soil-pile interaction. Helical piles can be a proper alternative in sensitive environmental sites if their bearing capacity is sufficient to support applied loads. The failure capacity of helical piles in this study was measured via an experimental research program that was carried out by Frustum Confining Vessel (FCV. FCV is a frustum chamber by approximately linear increase in vertical and lateral stresses along depth from top to bottom. Due to special geometry and applied bottom pressure, this apparatus is a proper choice to test small model piles which can simulate field stress conditions. Small scale helical piles are made with either single helix or more helixes and installed in fine grained sand with three various densities. Axial loading tests including compression and tension tests were performed to achieve pile ultimate capacity. The results indicate the helical piles behavior depends essentially on pile geometric characteristics, i.e. helix configuration and soil properties. According to the achievements, axial uplift capacity of helical model piles is about equal to usual steel model piles that have the helixes diameter. Helical pile compression bearing capacity is too sufficient to act as a medium pile, thus it can be substituted other piles in special geoenvironmental conditions. The bearing capacity also depends on spacing ratio, S/D, and helixes diameter.

  15. Acrylic vessel cleaning tests

    International Nuclear Information System (INIS)

    Earle, D.; Hahn, R.L.; Boger, J.; Bonvin, E.

    1997-01-01

    The acrylic vessel as constructed is dirty. The dirt includes blue tape, Al tape, grease pencil, gemak, the glue or residue form these tapes, finger prints and dust of an unknown composition but probably mostly acrylic dust. This dirt has to be removed and once removed, the vessel has to be kept clean or at least to be easily cleanable at some future stage when access becomes much more difficult. The authors report on the results of a series of tests designed: (a) to prepare typical dirty samples of acrylic; (b) to remove dirt stuck to the acrylic surface; and (c) to measure the optical quality and Th concentration after cleaning. Specifications of the vessel call for very low levels of Th which could come from tape residues, the grease pencil, or other sources of dirt. This report does not address the concerns of how to keep the vessel clean after an initial cleaning and during the removal of the scaffolding. Alconox is recommended as the cleaner of choice. This acrylic vessel will be used in the Sudbury Neutrino Observatory

  16. TMI-2 Vessel Investigation Project integration report

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, J. R.; Rempe, J. L.; Stickler, L. A.; Korth, G. E.; Diercks, D. R.; Neimark, L. A.; Akers, D W; Schuetz, B. K.; Shearer, T L; Chavez, S. A.; Thinnes, G. L.; Witt, R. J.; Corradini, M L; Kos, J. A. [EG and G Idaho, Inc., Idaho Falls, ID (United States)

    1994-03-01

    The Three Mile Island Unit 2 (TMI-2) Vessel Investigation Project (VIP) was an international effort that was sponsored by the Nuclear Energy Agency of the Organization for Economic Cooperation and Development. The primary objectives of the VIP were to extract and examine samples from the lower head and to evaluate the potential modes of failure and the margin of structural integrity that remained in the TMI-2 reactor vessel during the accident. This report presents a summary of the major findings and conclusions that were developed from research during the VIP. Results from the various elements of the project are integrated to form a cohesive understanding of the vessel`s condition after the accident.

  17. Uniformity of cylindrical imploding underwater shockwaves at very small radii

    Science.gov (United States)

    Yanuka, D.; Rososhek, A.; Bland, S. N.; Krasik, Ya. E.

    2017-11-01

    We compare the convergent shockwaves generated from underwater, cylindrical arrays of copper wire exploded by multiple kilo-ampere current pulses on nanosecond and microsecond scales. In both cases, the pulsed power devices used for the experiments had the same stored energy (˜500 J) and the wire mass was adjusted to optimize energy transfer to the shockwave. Laser backlit framing images of the shock front were achieved down to the radius of 30 μm. It was found that even in the case of initial azimuthal non-symmetry, the shock wave self-repairs in the final stages of its motion, leading to a highly uniform implosion. In both these and previous experiments, interference fringes have been observed in streak and framing images as the shockwave approached the axis. We have been able to accurately model the origin of the fringes, which is due to the propagation of the laser beam diffracting off the uniform converging shock front. The dynamics of the shockwave and its uniformity at small radii indicate that even with only 500 J stored energies, this technique should produce pressures above 1010 Pa on the axis, with temperatures and densities ideal for warm dense matter research.

  18. An underwater robot controls water tanks in nuclear power plants

    International Nuclear Information System (INIS)

    Lardiere, C.

    2015-01-01

    The enterprises Newton Research Labs and IHI Southwest Technologies have developed a robot equipped with sensors to inspect the inside walls (partially) and bottom of water tanks without being obliged to empty them. The robot called 'Inspector' is made up of 4 main components: a chassis with 4 independent steering wheels, a camera video system able to provide a 360 degree view, various non-destructive testing devices such as underwater laser scanners, automated ultra-sound or Foucault current probes and an operation system for both driving the robot and controlling the testing. The Inspector robot has been used to inspect the inside bottom of an operating condensate tank at the Palo Verde nuclear station. The robot was able to check all the welds joining the bottom plates and the welds between the walls and the bottom. The robot is also able to come back to the exact place where a defect was detected during a previous inspection. (A.C.)

  19. Studies of emulsification, emulsion prevention and underwater dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Celius, H.K.; Vassbotn, T.

    1985-03-01

    This is a report from the work performed under task 2: ''Effect of demulsifiers and despersants injected into a blowing oil stream'' of the research program ''Dispersion of oil on sea''. Three ad hoc experiments have been carried out involving laboratory studies in a small turbulent oil plume, tests with revolving flasks, and a small scale field test with a combined gas/oil plume. The results show that emulsion is formed in plume from underwater blowouts, and that this formation is prevented by small amounts (250 ppM) of demulsifiers or dispersants. Larger concentrations of dispersants (ca 2%) disperse the oil, and the oil is transported to the upper water layer in the gas/oil plume. None of the experiments have been designed as true scale tests, and the results cannot be directly transferred to operational, full scale conditions. The experiments have however narroved the necessary extent of studies, and allows for a simpler experimental procedure in the full scale field test planned for June 1985. 19 references.

  20. Sewage outfall plume dispersion observations with an autonomous underwater vehicle.

    Science.gov (United States)

    Ramos, P; Cunha, S R; Neves, M V; Pereira, F L; Quintaneiro, I

    2005-01-01

    This work represents one of the first successful applications of Autonomous Underwater Vehicles (AUVs) for interdisciplinary coastal research. A monitoring mission to study the shape and estimate the initial dilution of the S. Jacinto sewage outfall plume using an AUV was performed on July 2002. An efficient sampling strategy enabling greater improvements in spatial and temporal range of detection demonstrated that the sewage effluent plume can be clearly traced using naturally occurring tracers in the wastewater. The outfall plume was found at the surface highly influenced by the weak stratification and low currents. Dilution varying with distance downstream was estimated from the plume rise over the outfall diffuser until a nearly constant value of 130:1, 60 m from the diffuser, indicating the near field end. Our results demonstrate that AUVs can provide high-quality measurements of physical properties of effluent plumes in a very effective manner and valuable considerations about the initial mixing processes under real oceanic conditions can be further investigated.

  1. Upper limb joint forces and moments during underwater cyclical movements.

    Science.gov (United States)

    Lauer, Jessy; Rouard, Annie Hélène; Vilas-Boas, João Paulo

    2016-10-03

    Sound inverse dynamics modeling is lacking in aquatic locomotion research because of the difficulty in measuring hydrodynamic forces in dynamic conditions. Here we report the successful implementation and validation of an innovative methodology crossing new computational fluid dynamics and inverse dynamics techniques to quantify upper limb joint forces and moments while moving in water. Upper limb kinematics of seven male swimmers sculling while ballasted with 4kg was recorded through underwater motion capture. Together with body scans, segment inertial properties, and hydrodynamic resistances computed from a unique dynamic mesh algorithm capable to handle large body deformations, these data were fed into an inverse dynamics model to solve for joint kinetics. Simulation validity was assessed by comparing the impulse produced by the arms, calculated by integrating vertical forces over a stroke period, to the net theoretical impulse of buoyancy and ballast forces. A resulting gap of 1.2±3.5% provided confidence in the results. Upper limb joint load was within 5% of swimmer׳s body weight, which tends to supports the use of low-load aquatic exercises to reduce joint stress. We expect this significant methodological improvement to pave the way towards deeper insights into the mechanics of aquatic movement and the establishment of practice guidelines in rehabilitation, fitness or swimming performance. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. SHEBA Research Project D1.1

    DEFF Research Database (Denmark)

    Boteler, Benjamin; Tröltzsch, Jenny; Abhold, Katrina

    2015-01-01

    The objective of this report is to assess the current policy and socioeconomic drivers affecting shipping and other vessels globally and in the Baltic Sea region. The report provides a 'baseline' reference of key policy and socioeconomic drivers against which potential future changes to vessel ac...... a scenario that describes ship types and size, shipping routes, fuel mix in the sector and the use of technologies relevant for the environmental impact (scrubbers, NOX-abatement, ballast water systems, underwater noise, etc.)....

  3. Effect of the in- and ex-vessel dual cooling on the retention of an internally heated melt pool in a hemispherical vessel

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, K.I.; Kim, B.S.; Kim, D.H. [Korea Atomic Energy Research Inst., Thermal Hydraulic Safety Research, Taejon (Korea, Republic of)

    2001-07-01

    A concept of in-vessel melt retention (IVMR) by in-vessel reflooding and/or reactor cavity flooding has been considered as one of severe accident management strategies and intensive researches to be performed worldwide. This paper provides some results of analytical investigations on the effect of both in- / ex-vessel cooling on the retention of an internally heated molten pool confined in a hemispherical vessel and the related thermal behavior of the vessel wall. For the present analysis, a scale-down reactor vessel for the KSNP reactor design of 1000 MWe (a large dry PWR) is utilized for a reactor vessel. Aluminum oxide melt simulant is also utilized for a real corium pool. An internal power density in the molten pool is determined by a simple scaling analysis that equates the heat flux on the the scale-down vessel wall to that estimated from KSNP. Well-known temperature-dependent boiling heat transfer curves are applied to the in- and ex-vessel cooling boundaries and radiative heat transfer has been only considered in the case of dry in-vessel. MELTPOOL, which is a computational fluid dynamics (CFD) code developed at KAERI, is applied to obtain the time-varying heat flux distribution from a molten pool and the vessel wall temperature distributions with angular positions along the vessel wall. In order to gain further insights on the effectiveness of in- and ex-vessel dual cooling on the in-vessel corium retention, four different boundary conditions has been considered: no water inside the vessel without ex-vessel cooling, water inside the vessel without ex-vessel cooling, no water inside the vessel with ex-vessel cooling, and water inside the vessel with ex-vessel cooling. (authors)

  4. Effect of the in- and ex-vessel dual cooling on the retention of an internally heated melt pool in a hemispherical vessel

    International Nuclear Information System (INIS)

    Ahn, K.I.; Kim, B.S.; Kim, D.H.

    2001-01-01

    A concept of in-vessel melt retention (IVMR) by in-vessel reflooding and/or reactor cavity flooding has been considered as one of severe accident management strategies and intensive researches to be performed worldwide. This paper provides some results of analytical investigations on the effect of both in- / ex-vessel cooling on the retention of an internally heated molten pool confined in a hemispherical vessel and the related thermal behavior of the vessel wall. For the present analysis, a scale-down reactor vessel for the KSNP reactor design of 1000 MWe (a large dry PWR) is utilized for a reactor vessel. Aluminum oxide melt simulant is also utilized for a real corium pool. An internal power density in the molten pool is determined by a simple scaling analysis that equates the heat flux on the the scale-down vessel wall to that estimated from KSNP. Well-known temperature-dependent boiling heat transfer curves are applied to the in- and ex-vessel cooling boundaries and radiative heat transfer has been only considered in the case of dry in-vessel. MELTPOOL, which is a computational fluid dynamics (CFD) code developed at KAERI, is applied to obtain the time-varying heat flux distribution from a molten pool and the vessel wall temperature distributions with angular positions along the vessel wall. In order to gain further insights on the effectiveness of in- and ex-vessel dual cooling on the in-vessel corium retention, four different boundary conditions has been considered: no water inside the vessel without ex-vessel cooling, water inside the vessel without ex-vessel cooling, no water inside the vessel with ex-vessel cooling, and water inside the vessel with ex-vessel cooling. (authors)

  5. Radioactive liquid containing vessel

    International Nuclear Information System (INIS)

    Sakurada, Tetsuo; Kawamura, Hironobu.

    1993-01-01

    Cooling jackets are coiled around the outer circumference of a container vessel, and the outer circumference thereof is covered with a surrounding plate. A liquid of good conductivity (for example, water) is filled between the cooling jackets and the surrounding plate. A radioactive liquid is supplied to the container vessel passing through a supply pipe and discharged passing through a discharge pipe. Cooling water at high pressure is passed through the cooling water jackets in order to remove the heat generated from the radioactive liquid. Since cooling water at high pressure is thus passed through the coiled pipes, the wall thickness of the container vessel and the cooling water jackets can be reduced, thereby enabling to reduce the cost. Further, even if the radioactive liquid is leaked, there is no worry of contaminating cooling water, to prevent contamination. (I.N.)

  6. Underwater hydraulic shock shovel control system

    Science.gov (United States)

    Liu, He-Ping; Luo, A.-Ni; Xiao, Hai-Yan

    2008-06-01

    The control system determines the effectiveness of an underwater hydraulic shock shovel. This paper begins by analyzing the working principles of these shovels and explains the importance of their control systems. A new type of control system’s mathematical model was built and analyzed according to those principles. Since the initial control system’s response time could not fulfill the design requirements, a PID controller was added to the control system. System response time was still slower than required, so a neural network was added to nonlinearly regulate the proportional element, integral element and derivative element coefficients of the PID controller. After these improvements to the control system, system parameters fulfilled the design requirements. The working performance of electrically-controlled parts such as the rapidly moving high speed switch valve is largely determined by the control system. Normal control methods generally can’t satisfy a shovel’s requirements, so advanced and normal control methods were combined to improve the control system, bringing good results.

  7. Data extraction system for underwater particle holography

    Science.gov (United States)

    Nebrensky, J. J.; Craig, Gary; Hobson, Peter R.; Lampitt, R. S.; Nareid, Helge; Pescetto, A.; Trucco, Andrea; Watson, John

    2000-08-01

    Pulsed laser holography in an extremely powerful technique for the study of particle fields as it allows instantaneous, non-invasive high- resolution recording of substantial volumes. By relaying the real image one can obtain the size, shape, position and - if multiple exposures are made - velocity of every object in the recorded field. Manual analysis of large volumes containing thousands of particles is, however, an enormous and time-consuming task, with operator fatigue an unpredictable source of errors. Clearly the value of holographic measurements also depends crucially on the quality of the reconstructed image: not only will poor resolution degrade the size and shape measurements, but aberrations such as coma and astigmatism can change the perceived centroid of a particle, affecting position and velocity measurements. For large-scale applications of particle field holography, specifically the in situ recording of marine plankton with Holocam, we have developed an automated data extraction system that can be readily switched between the in-line and off-axis geometries and provides optimised reconstruction from holograms recorded underwater. As a videocamera is automatically stepped through the 200 by 200 by 1000mm sample volume, image processing and object tracking routines locate and extract particle images for further classification by a separate software module.

  8. Predictive Model for the Analysis of the Effects of Underwater Impulsive Sources on Marine Life

    National Research Council Canada - National Science Library

    Lazauski, Colin J

    2007-01-01

    A method is provided to predict the biological consequences to marine animals from exposure to multiple underwater impulsive sources by simulating underwater explosions over a defined period of time...

  9. A Framework for Evaluating Advanced Search Concepts for Multiple Autonomous Underwater Vehicle (AUV) Mine Countermeasures (MCM)

    National Research Council Canada - National Science Library

    Gooding, Trent

    2001-01-01

    .... In recent years, autonomous underwater vehicles (AUV) have emerged as a viable technology for conducting underwater search, survey, and clearance operations in support of the mine countermeasures (MCM) mission...

  10. A Game-theoretical Approach for Distributed Cooperative Control of Autonomous Underwater Vehicles

    KAUST Repository

    Lu, Yimeng

    2018-01-01

    design and learning process of the algorithm are modified to fit specific constraints of underwater exploration/monitoring tasks. The revised approach can take the real scenario of underwater monitoring applications such as the effect of sea current

  11. Design and Evaluation Methods for Underwater Control Systems

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Lin

    1996-12-31

    This thesis on underwater control systems is written with the designer in mind, assuming that the reader has some knowledge of control theory. It can be used as a text for undergraduate students and engineers. To help readers better understand the system they will be working with, the thesis is organised in a stepwise way. The reader will gain basic knowledge about underwater operations, equipment and control systems. Then the reader will be able to follow the steps to develop a required control system for an underwater equipment by first understanding the characteristics of the design problem, customer requirement, functional requirement, and possible solution, and then to present a mathematical model of the control problem. Having developed the concept, the thesis guides the reader to develop evaluation criteria and different ways to make the decision. The thesis gives an overview of how to achieve a successful design rather than giving the techniques for detailed control system design. Chapter 1 describes underwater operations and systems. Chapter 2 discusses issues of underwater control systems and control methods. Chapter 3 deals with design method and control systems theory, focusing on human-centered control. Chapter 4 discusses methods used to evaluate and rank products, and chapter 5 applies the methods to an example. 113 refs., 115 figs., 80 tabs.

  12. Feasibility of in situ beta ray measurements in underwater environment.

    Science.gov (United States)

    Park, Hye Min; Park, Ki Hyun; Kang, Sung Won; Joo, Koan Sik

    2017-09-01

    We describe an attempt at the development of an in situ detector for beta ray measurements in underwater environment. The prototype of the in situ detector is based on a CaF2: Eu scintillator using crystal light guide and Si photomultiplier. Tests were conducted using various reference sources for evaluating the linearity and stability of the detector in underwater environment. The system is simple and stable for long-term monitoring, and consumes low power. We show here an effective detection distance of 7 mm and a 2.273 MeV end-point energy spectrum of 90 Sr/ 90 Y when using the system underwater. The results demonstrate the feasibility of in situ beta ray measurements in underwater environment and can be applied for designing an in situ detector for radioactivity measurement in underwater environment. The in situ detector can also have other applications such as installation on the marine monitoring platform and quantitative analysis of radionuclides. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Design and Evaluation Methods for Underwater Control Systems

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Lin

    1997-12-31

    This thesis on underwater control systems is written with the designer in mind, assuming that the reader has some knowledge of control theory. It can be used as a text for undergraduate students and engineers. To help readers better understand the system they will be working with, the thesis is organised in a stepwise way. The reader will gain basic knowledge about underwater operations, equipment and control systems. Then the reader will be able to follow the steps to develop a required control system for an underwater equipment by first understanding the characteristics of the design problem, customer requirement, functional requirement, and possible solution, and then to present a mathematical model of the control problem. Having developed the concept, the thesis guides the reader to develop evaluation criteria and different ways to make the decision. The thesis gives an overview of how to achieve a successful design rather than giving the techniques for detailed control system design. Chapter 1 describes underwater operations and systems. Chapter 2 discusses issues of underwater control systems and control methods. Chapter 3 deals with design method and control systems theory, focusing on human-centered control. Chapter 4 discusses methods used to evaluate and rank products, and chapter 5 applies the methods to an example. 113 refs., 115 figs., 80 tabs.

  14. A bio-inspired electrocommunication system for small underwater robots.

    Science.gov (United States)

    Wang, Wei; Liu, Jindong; Xie, Guangming; Wen, Li; Zhang, Jianwei

    2017-03-29

    Weakly electric fishes (Gymnotid and Mormyrid) use an electric field to communicate efficiently (termed electrocommunication) in the turbid waters of confined spaces where other communication modalities fail. Inspired by this biological phenomenon, we design an artificial electrocommunication system for small underwater robots and explore the capabilities of such an underwater robotic communication system. An analytical model for electrocommunication is derived to predict the effect of the key parameters such as electrode distance and emitter current of the system on the communication performance. According to this model, a low-dissipation, and small-sized electrocommunication system is proposed and integrated into a small robotic fish. We characterize the communication performance of the robot in still water, flowing water, water with obstacles and natural water conditions. The results show that underwater robots are able to communicate electrically at a speed of around 1 k baud within about 3 m with a low power consumption (less than 1 W). In addition, we demonstrate that two leader-follower robots successfully achieve motion synchronization through electrocommunication in the three-dimensional underwater space, indicating that this bio-inspired electrocommunication system is a promising setup for the interaction of small underwater robots.

  15. Experimental Study on the Measurement of Water Bottom Vibration Induced by Underwater Drilling Blasting

    OpenAIRE

    Wenbin, Gu; Jianghai, Chen; Zhenxiong, Wang; Zhihua, Wang; Jianqing, Liu; Ming, Lu

    2015-01-01

    Due to the lack of proper instrumentations and the difficulties in underwater measurements, the studies about water bottom vibration induced by underwater drilling blasting are seldom reported. In order to investigate the propagation and attenuation laws of blasting induced water bottom vibration, a water bottom vibration monitor was developed with consideration of the difficulties in underwater measurements. By means of this equipment, the actual water bottom vibration induced by underwater ...

  16. Kinematic and EMG data during underwater dolphin kick change while synchronizing with or without synchronization of kick frequency with the beat of a metronome.

    Science.gov (United States)

    Yamakawa, Keisuke Kobayashi; Shimojo, Hirofumi; Takagi, Hideki; Tsubakimoto, Shozo; Sengoku, Yasuo

    2017-10-01

    We investigated the effects of synchronizing kick frequency with the beat of a metronome on kinematic and electromyographic (EMG) parameters during the underwater dolphin kick as a pilot study related to the research that entitled " Effect of increased kick frequency on propelling efficiency and muscular co-activation during underwater dolphin kick" (Yamakawa et al., 2017) [1]. Seven collegiate female swimmers participated in this experiment. The participants conducted two underwater dolphin kick trials: swimming freely at maximum effort, and swimming while synchronizing the kick frequency of maximum effort with the beat of a metronome. The kinematic parameters during the underwater dolphin kick were calculated by 2-D motion analysis, and surface electromyographic measurements were taken from six muscles (rectus abdominis, erector spinae, rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius). The results revealed no significant differences in the kinematic and EMG parameters between trials of the two swimming techniques. Therefore, the action of synchronizing the kick frequency with the beat of a metronome did not affect movement or muscle activity during the underwater dolphin kick in this experiment.

  17. Kinematic and EMG data during underwater dolphin kick change while synchronizing with or without synchronization of kick frequency with the beat of a metronome

    Directory of Open Access Journals (Sweden)

    Keisuke Kobayashi Yamakawa

    2017-10-01

    Full Text Available We investigated the effects of synchronizing kick frequency with the beat of a metronome on kinematic and electromyographic (EMG parameters during the underwater dolphin kick as a pilot study related to the research that entitled “Effect of increased kick frequency on propelling efficiency and muscular co-activation during underwater dolphin kick” (Yamakawa et al., 2017 [1]. Seven collegiate female swimmers participated in this experiment. The participants conducted two underwater dolphin kick trials: swimming freely at maximum effort, and swimming while synchronizing the kick frequency of maximum effort with the beat of a metronome. The kinematic parameters during the underwater dolphin kick were calculated by 2-D motion analysis, and surface electromyographic measurements were taken from six muscles (rectus abdominis, erector spinae, rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius. The results revealed no significant differences in the kinematic and EMG parameters between trials of the two swimming techniques. Therefore, the action of synchronizing the kick frequency with the beat of a metronome did not affect movement or muscle activity during the underwater dolphin kick in this experiment.

  18. Modelling of in-vessel retention after relocation of corium into the lower plenum - Evaluation of the temperature field and of the viscoplastic deformation of the vessel wall. Reactor safety research, project No.:150 1254 - Final report; Beitrag zur Modellierung der Schmelzerueckhaltung im RDB nach Verlagerung von Corium in das untere Plenum - Berechnung des Temperaturfeldes und der viskoplastischen Verformung der Behaelterwand. Reaktorsicherheitsforschung, Vorhaben-Nr.: 150 1254 - Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Altstadt, E.; Willschuetz, H.G. [Forschungszentrum Rossendorf e.V. (FZR), Dresden (Germany)

    2005-01-01

    Considering the hypothetical core melt down scenario for a light water reactor (LWR) a possible failure mode of the reactor pressure vessel (RPV) and its failure time has to be investigated for a determination of the loadings on the containment. Several experiments have been performed accompanied with material properties evaluation, theoretical, and numerical work. At the Institute Of Safety Research of the FZR a finite element model has been developed simulating the thermal processes and the viscoplastic behaviour of the vessel wall. An advanced model for creep and material damage has been established and has been validated using experimental data. The thermal hydraulic and the mechanical calculations are sequentially and recursively coupled. The model is capable of evaluating fracture time and fracture position of a vessel with an internally heated melt pool. The model was applied to pre- and post test calculations for the FOREVER test series representing the RPV of a PWR in the scale of 1:10. These experiments were performed at the Royal Institute of Technology in Stockholm. The results of the calculations can be summarised as follows: The creeping process is caused by the simultaneous presence of high temperature (>600 C) and pressure (>1 MPa). The hot focus region is the most endangered zone exhibiting the highest creep strain rates. The exact level of temperature and pressure has an influence on the vessel failure time but not on the failure position. The failure time can be predicted with an uncertainty of 20 to 25%. This uncertainty is caused by the large scatter and the high temperature sensitivity of the viscoplastic properties of the RPV steel. Contrary to the hot focus region, the lower centre of the vessel head exhibits a higher strength because of the lower temperatures in this zone. The lower part moves down without significant deformation. Therefore it can be assumed, that the vessel failure can be retarded or prevented by supporting this range. The

  19. Underwater coating repair cuts nuclear maintenance costs

    International Nuclear Information System (INIS)

    Stuart, C.O.

    1993-01-01

    This article discusses the cleaning and recoating/repair of condensate tanks or other vessels in a nuclear power plant. The topics of the article include the safety and regulatory need for this system of repair, a description of the work done on the Brown's Ferry MK-1 suppression chamber, coating failure mechanisms, qualitative inspection, quantitative inspection, quantitative inspection results, spot repairs, and economic considerations

  20. Underwater wireless optical communications: From system-level demonstrations to channel modelling

    KAUST Repository

    Oubei, Hassan M.

    2018-01-09

    In this paper, we discuss about recent experimental advances in underwater wireless optical communications (UWOC) over various underwater channel water types using different modulation schemes as well as modelling and describing the statistical properties of turbulence-induced fading in underwater wireless optical channels using laser beam intensity fluctuations measurements.

  1. Efficient Weibull channel model for salinity induced turbulent underwater wireless optical communications

    KAUST Repository

    Oubei, Hassan M.

    2017-12-13

    Recent advances in underwater wireless optical communications necessitate a better understanding of the underwater channel. We propose the Weibull model to characterize the fading of salinity induced turbulent underwater wireless optical channels. The model shows an excellent agreement with the measured data under all channel conditions.

  2. Pressure vessel integrity 1991

    International Nuclear Information System (INIS)

    Bhandari, S.; Doney, R.O.; McDonald, M.S.; Jones, D.P.; Wilson, W.K.; Pennell, W.E.

    1991-01-01

    This volume contains papers relating to the structural integrity assessment of pressure vessels and piping, with special emphasis on nuclear industry applications. The papers were prepared for technical sessions developed under the sponsorship of the ASME Pressure Vessels and Piping Division Committees for Codes and Standards, Computer Technology, Design and Analysis, and Materials Fabrication. They were presented at the 1991 Pressure Vessels and Piping Division Conference in San Diego, California, June 23-27. The primary objective of the sponsoring organization is to provide a forum for the dissemination and discussion of information on development and application of technology for the structural integrity assessment of pressure vessels and piping. This publication includes contributions from authors from Australia, France, Japan, Sweden, Switzerland, the United Kingdom, and the United States. The papers here are organized in six sections, each with a particular emphasis as indicated in the following section titles: Fracture Technology Status and Application Experience; Crack Initiation, Propagation and Arrest; Ductile Tearing; Constraint, Stress State, and Local-Brittle-Zones Effects; Computational Techniques for Fracture and Corrosion Fatigue; and Codes and Standards for Fatigue, Fracture and Erosion/Corrosion

  3. The reactor vessel steels

    International Nuclear Information System (INIS)

    Bilous, W.; Hajewska, E.; Szteke, W.; Przyborska, M.; Wasiak, J.; Wieczorkowski, M.

    2005-01-01

    In the paper the fundamental steels using in the construction of pressure vessel water reactor are discussed. The properties of these steels as well as the influence of neutron irradiation on its degradation in the time of exploitation are also done. (authors)

  4. Vacuum distilling vessel

    Energy Technology Data Exchange (ETDEWEB)

    Reik, H

    1928-12-27

    Vacuum distilling vessel for mineral oil and the like, characterized by the ring-form or polyconal stiffeners arranged inside, suitably eccentric to the casing, being held at a distance from the casing by connecting members of such a height that in the resulting space if necessary can be arranged vapor-distributing pipes and a complete removal of the residue is possible.

  5. GOLD PRESSURE VESSEL SEAL

    Science.gov (United States)

    Smith, A.E.

    1963-11-26

    An improved seal between the piston and die member of a piston-cylinder type pressure vessel is presented. A layer of gold, of sufficient thickness to provide an interference fit between the piston and die member, is plated on the contacting surface of at least one of the members. (AEC)

  6. Reactor vessel stud tensioner

    International Nuclear Information System (INIS)

    Malandra, L.J.; Beer, R.W.; Salton, R.B.; Spiegelman, S.R.; Cognevich, M.L.

    1982-01-01

    A quick-acting stud tensioner, for facilitating the loosening or tightening of a stud nut on a reactor vessel stud, has gripper jaws which when the tensioner is lowered into engagement with the upper end of the stud are moved inwards to grip the upper end and which when the tensioner is lifted move outward to release the upper end. (author)

  7. The pressure vessel for the NSF tandem

    International Nuclear Information System (INIS)

    Jones, C.W.

    1979-04-01

    The pressure vessel is a major component of the 30 MV tandem Van de Graaff electrostatic accelerator to be used in nuclear structure research at Daresbury Laboratory. The accelerator will be capable of accelerating the full range of ions in the form of a beam. Acceleration takes place in a vertical evacuated tube (beam tube) by means of a high potential on a terminal at the central position, the terminal and beam tube assembly being supported by an insulated stack structure within the pressure vessel. Under operating conditions the vessel is filled with sulphur hexafluoride gas (SF 6 ) at high pressure which acts as an insulating medium between the centre terminal and the vessel wall. The vessel is situated inside a concrete tower which besides supporting the injector room above the vessel also acts as radiation shielding around the accelerator. The report covers: functional requirements; fundamental considerations with regard to the design and procurement; detail design; materials; manufacture; acceptance test; surface treatment; final leak test. (U.K.)

  8. Impacts of Underwater Noise on Marine Vertebrates: Project Introduction and First Results.

    Science.gov (United States)

    Liebschner, Alexander; Seibel, Henrike; Teilmann, Jonas; Wittekind, Dietrich; Parmentier, Eric; Dähne, Michael; Dietz, Rune; Driver, Jörg; van Elk, Cornelis; Everaarts, Eligius; Findeisen, Henning; Kristensen, Jacob; Lehnert, Kristina; Lucke, Klaus; Merck, Thomas; Müller, Sabine; Pawliczka, Iwona; Ronnenberg, Katrin; Rosenberger, Tanja; Ruser, Andreas; Tougaard, Jakob; Schuster, Max; Sundermeyer, Janne; Sveegaard, Signe; Siebert, Ursula

    2016-01-01

    The project conducts application-oriented research on impacts of underwater noise on marine vertebrates in the North and Baltic Seas. In distinct subprojects, the hearing sensitivity of harbor porpoises and gray seals as well as the acoustic tolerance limit of harbor porpoises to impulsive noise from pile driving and stress reactions caused by anthropogenic noise is investigated. Animals are equipped with DTAGs capable of recording the actual surrounding noise field of free-swimming harbor porpoises and seals. Acoustic noise mapping including porpoise detectors in the Natura 2000 sites of the North and Baltic Seas will help to fully understand current noise impacts.

  9. Advanced Approach of Reactor Pressure Vessel In-service Inspection

    International Nuclear Information System (INIS)

    Matokovic, A.; Picek, E.; Pajnic, M.

    2006-01-01

    The most important task of every utility operating a nuclear power plant is the continuously keeping of the desired safety and reliability level. This is achieved by the performance of numerous inspections of the components, equipment and system of the nuclear power plant in operation and in particular during the scheduled maintenance periods at re-fueling time. Periodic non-destructive in-service inspections provide most relevant criteria of the integrity of primary circuit pressure components. The task is to reliably detect defects and realistically size and characterize them. One of most important and the most extensive examination is a reactor pressure vessel in-service inspection. That inspection demand high standards of technology and quality and continual innovation in the field of non-destructive testing (NDT) advanced technology as well as regarding reactor pressure vessel tool and control systems. A remote underwater contact ultrasonic technique is employed for the examination of the defined sections (reactor welds), whence eddy current method is applied for clad surface examinations. Visual inspection is used for examination of the vessel inner surface. The movement of probes and data positioning are assured by using new reactor pressure vessel tool concept that is fully integrated with NDT systems. The successful performance is attributed thorough pre-outage planning, training and successful performance demonstration qualification of chosen NDT techniques on the specimens with artificial and/or real defects. Furthermore, use of advanced approach of inspection through implementation the state of the art examination equipment significantly reduced the inspection time, radiation exposure to examination personnel, shortening nuclear power plant outage and cutting the total inspection costs. The advanced approach as presented in this paper offer more flexibility of application (non-destructive tests, local grinding action as well as taking of boat samples

  10. Experimental study on underwater electrical explosion of a copper wire

    International Nuclear Information System (INIS)

    Zhou Qing; Zhang Jun; Tan Xiangyu; Ren Baozhong; Zhang Qiaogen

    2010-01-01

    Through analyzing the physical process of underwater electrical wire explosion, electrical wire explosions with copper wires were investigated underwater using pulsed voltage in the time scale of a few microseconds. A self-integrating Rogowsky coil and a voltage divider were used for current and voltage at the wire load, respectively. The shock wave pressure is measured with a piezoelectric pressure probe at the same distance. The current rise rate was adjusted by changing the applied voltage, circuit inductance, length and diameter of copper wire. The change of the current rise rate had a great effect on the process of underwater electrical wire explosion with copper wires. At last, the effect of discharge voltage, circuit inductance, length and diameter of copper wire were obtained on the explosion voltage and current as well as shock wave pressure. (authors)

  11. Optimal Node Placement in Underwater Wireless Sensor Networks

    KAUST Repository

    Felamban, M.

    2013-03-25

    Wireless Sensor Networks (WSN) are expected to play a vital role in the exploration and monitoring of underwater areas which are not easily reachable by humans. However, underwater communication via acoustic waves is subject to several performance limitations that are very different from those used for terresstrial networks. In this paper, we investigate node placement for building an initial underwater WSN infrastructure. We formulate this problem as a nonlinear mathematical program with the objective of minimizing the total transmission loss under a given number of sensor nodes and targeted coverage volume. The obtained solution is the location of each node represented via a truncated octahedron to fill out the 3D space. Experiments are conducted to verify the proposed formulation, which is solved using Matlab optimization tool. Simulation is also conducted using an ns-3 simulator, and the simulation results are consistent with the obtained results from mathematical model with less than 10% error.

  12. Underwater video enhancement using multi-camera super-resolution

    Science.gov (United States)

    Quevedo, E.; Delory, E.; Callicó, G. M.; Tobajas, F.; Sarmiento, R.

    2017-12-01

    Image spatial resolution is critical in several fields such as medicine, communications or satellite, and underwater applications. While a large variety of techniques for image restoration and enhancement has been proposed in the literature, this paper focuses on a novel Super-Resolution fusion algorithm based on a Multi-Camera environment that permits to enhance the quality of underwater video sequences without significantly increasing computation. In order to compare the quality enhancement, two objective quality metrics have been used: PSNR (Peak Signal-to-Noise Ratio) and the SSIM (Structural SIMilarity) index. Results have shown that the proposed method enhances the objective quality of several underwater sequences, avoiding the appearance of undesirable artifacts, with respect to basic fusion Super-Resolution algorithms.

  13. H∞ control for path tracking of autonomous underwater vehicle motion

    Directory of Open Access Journals (Sweden)

    Lin-Lin Wang

    2015-05-01

    Full Text Available In order to simplify the design of path tracking controller and solve the problem relating to nonlinear dynamic model of autonomous underwater vehicle motion planning, feedback linearization method is first adopted to transform the nonlinear dynamic model into an equivalent pseudo-linear dynamic model in horizontal coordinates. Then considering wave disturbance effect, mixed-sensitivity method of H∞ robust control is applied to design state-feedback controller for this equivalent dynamic model. Finally, control law of pseudo-linear dynamic model is transformed into state (surge velocity and yaw angular rate tracking control law of nonlinear dynamic model through inverse coordinate transformation. Simulation indicates that autonomous underwater vehicle path tracking is successfully implemented with this proposed method, and the influence of parameter variation in autonomous underwater vehicle dynamic model on its tracking performance is reduced by H∞ controller. All the results show that the method proposed in this article is effective and feasible.

  14. Automated gravity gradient tensor inversion for underwater object detection

    International Nuclear Information System (INIS)

    Wu, Lin; Tian, Jinwen

    2010-01-01

    Underwater abnormal object detection is a current need for the navigation security of autonomous underwater vehicles (AUVs). In this paper, an automated gravity gradient tensor inversion algorithm is proposed for the purpose of passive underwater object detection. Full-tensor gravity gradient anomalies induced by an object in the partial area can be measured with the technique of gravity gradiometry on an AUV. Then the automated algorithm utilizes the anomalies, using the inverse method to estimate the mass and barycentre location of the arbitrary-shaped object. A few tests on simple synthetic models will be illustrated, in order to evaluate the feasibility and accuracy of the new algorithm. Moreover, the method is applied to a complicated model of an abnormal object with gradiometer and AUV noise, and interference from a neighbouring illusive smaller object. In all cases tested, the estimated mass and barycentre location parameters are found to be in good agreement with the actual values

  15. Underwater Time Service and Synchronization Based on Time Reversal Technique

    Science.gov (United States)

    Lu, Hao; Wang, Hai-bin; Aissa-El-Bey, Abdeldjalil; Pyndiah, Ramesh

    2010-09-01

    Real time service and synchronization are very important to many underwater systems. But the time service and synchronization in existence cannot work well due to the multi-path propagation and random phase fluctuation of signals in the ocean channel. The time reversal mirror technique can realize energy concentration through self-matching of the ocean channel and has very good spatial and temporal focusing properties. Based on the TRM technique, we present the Time Reversal Mirror Real Time service and synchronization (TRMRT) method which can bypass the processing of multi-path on the server side and reduce multi-path contamination on the client side. So TRMRT can improve the accuracy of time service. Furthermore, as an efficient and precise method of time service, TRMRT could be widely used in underwater exploration activities and underwater navigation and positioning systems.

  16. Gas-liquid contacting in mixing vessels

    International Nuclear Information System (INIS)

    Mann, R.

    1983-01-01

    This report by Dr. R. Mann of UMIST presents a critical survey of literature on the contacting of gases with liquids in stirred vessels. Research undertaken in the last fifteen years in analysed, and promising areas for future research are identified. The report deals with physical contacting, mass transfer between the gas and liquid phases and the utilisation of the stirred vessel as a gas-liquid reactor. Three sections are given on gas-liquid contacting: physical aspects; interphase mass transfer; and chemical reactions. It also discusses recent new approaches and includes a summary of conclusions, nomenclature and references

  17. PDX vacuum vessel stress analysis

    International Nuclear Information System (INIS)

    Nikodem, Z.D.

    1975-01-01

    A stress analysis of PDX vacuum vessel is described and the summary of results is presented. The vacuum vessel is treated as a toroidal shell of revolution subjected to an internal vacuum. The critical buckling pressure is calculated. The effects of the geometrical discontinuity at the juncture of toroidal shell head and cylindrical outside wall, and the concavity of the cylindrical wall are examined. An effect of the poloidal field coil supports and the vessel outside supports on the stress distribution in the vacuum vessel is determined. A method evaluating the influence of circular ports in the vessel wall on the stress level in the vessel is outlined

  18. Development of a compact underwater laser-induced breakdown spectroscopy (LIBS) system and preliminary results in sea trials.

    Science.gov (United States)

    Guo, Jinjia; Lu, Yuan; Cheng, Kai; Song, Jiaojian; Ye, Wangquan; Li, Nan; Zheng, Ronger

    2017-10-10

    The exploitation and research of deep-sea hydrothermal vent has been an issue of great interest in ocean research in recent years. Laser-induced breakdown spectroscopy (LIBS) has great potential for ocean application due to the capabilities of stand-off, multiphase, and multielement analysis. In this work, a newly developed compact 4000 m rated LIBS system (LIBSea) is introduced with preliminary results of sea trials. The underwater system consists of an Nd:YAG single-pulsed laser operating at 1064 nm, an optical fiber spectrometer, an optics module, and an electronic controller module. The whole system is housed in an L800  mm×ϕ258  mm pressure housing with an optical window on the end cap. It was deployed on the remote operated vehicle Faxian on the research vessel Kexue, and in June 2015 was successfully applied for hydrothermal field measurements at the Manus area. The obtained results are shown that the LIBS system is capable of detecting elements Li, Na, K, Ca, and Mg in the hydrothermal area. Profiles of LIBS signals of elements K and Ca have also been obtained during the sea trial. The results show that the K emission line is gradually broadened with depth from sea surface to sea floor (1800 m or so); the K intensity shows a hump shape with maximum value at about 1050 m. The Ca emission line is rapidly broadened below 400 m and slowly narrowed to the sea floor; the Ca intensity shows no obvious change below 400 m and increases continuously to sea floor. A very interesting finding is that the small fluctuations of intensity profile curve of Ca show a degree of correlation with seawater temperature change. The sea trial results prove the performance of LIBSea. After further optimization, it is hoped to apply the LIBS system to the in situ mineral deposits and hydrothermal vent fluid detection in deep sea.

  19. Time-of-flight range imaging for underwater applications

    Science.gov (United States)

    Merbold, Hannes; Catregn, Gion-Pol; Leutenegger, Tobias

    2018-02-01

    Precise and low-cost range imaging in underwater settings with object distances on the meter level is demonstrated. This is addressed through silicon-based time-of-flight (TOF) cameras operated with light emitting diodes (LEDs) at visible, rather than near-IR wavelengths. We find that the attainable performance depends on a variety of parameters, such as the wavelength dependent absorption of water, the emitted optical power and response times of the LEDs, or the spectral sensitivity of the TOF chip. An in-depth analysis of the interplay between the different parameters is given and the performance of underwater TOF imaging using different visible illumination wavelengths is analyzed.

  20. Airborne lidar detection of an underwater thermal vent

    Science.gov (United States)

    Roddewig, Michael R.; Churnside, James H.; Shaw, Joseph A.

    2017-07-01

    We report the lidar detection of an underwater feature that appears to be a thermal vent in Yellowstone Lake, Yellowstone National Park, USA, with the Montana State University Fish Lidar. The location of the detected vent was 30 m from the closest vent identified in a United States Geological Survey of Yellowstone Lake in 2008. A second possible vent is also presented, and the appearance of both vents in the lidar data is compared to descriptions of underwater thermal vents in Yellowstone Lake from the geological literature.

  1. Reduced Attitude Control of a Robotic Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Bláha Lukáš

    2017-01-01

    Full Text Available This paper deals with stabilization and reduced attitude control of a robotic underwater vehicle. The vehicle is assumed to be able to perform a full stable rotations around all axes in underwater space, that is why the standard bottom-heavy structure is not used. The system preferably uses a vectored-thrust arrangement and is built as an overactuated system, which enables to gain a better robustness and guarantees a stable controlled motion even if some thruster suddenly stop working. Because the heading angle cannot be measured, the reduced attitude control strategy is designed and the stability of reduced state of the system is proved using perturbation method.

  2. 3D MODELING FOR UNDERWATER ARCHAEOLOGICAL DOCUMENTATION: METRIC VERIFICATIONS

    Directory of Open Access Journals (Sweden)

    S. D’Amelio

    2015-04-01

    Full Text Available The survey in underwater environment has always presented considerable difficulties both operative and technical and this has sometimes made it difficult to use the techniques of survey commonly used for the documentation of Cultural Heritage in dry environment. The work of study concerns the evaluation in terms of capability and accuracy of the Autodesk123DCatch software for the reconstruction of a three-dimensional model of an object in underwater context. The subjects of the study are models generated from sets of photographs and sets of frames extracted from video sequence. The study is based on comparative method, using a reference model, obtained with laser scanner technique.

  3. Study of underwater laser propulsion using different target materials.

    Science.gov (United States)

    Qiang, Hao; Chen, Jun; Han, Bing; Shen, Zhong-Hua; Lu, Jian; Ni, Xiao-Wu

    2014-07-14

    In order to investigate the influence of target materials, including aluminum (Al), titanium (Ti) and copper (Cu), on underwater laser propulsion, the analytical formula of the target momentum IT is deduced from the enhanced coupling theory of laser propulsion in atmosphere with transparent overlay metal target. The high-speed photography method and numerical simulation are employed to verify the IT model. It is shown that the enhanced coupling theory, which was developed originally for laser propulsion in atmosphere, is also applicable to underwater laser propulsion with metal targets.

  4. United States Nuclear Regulatory Commission research program on core debris/concrete interactions and ex-vessel fission-product release

    International Nuclear Information System (INIS)

    Burson, S.B.

    1987-01-01

    The study of core debris/concrete interaction phenomena has been a significant element of the NRC's Severe Accident Research Program for a number of years. The CORCON and VANESA codes used to predict the consequences of high-temperature debris attack on concrete and fission-product aerosol release are state-of-the-art computational tools. The major thrust of current NRC sponsored research focuses on the refinement, verification, and validation of these codes. An overview of the analytical and experimental aspects of the NRC research program is presented

  5. Procurement of replacement pressure vessels for MURR

    International Nuclear Information System (INIS)

    Meyer, W.A. Jr.; Edwards, C.B. Jr.; McKibben, J.C.; Schoone, A.R.

    1989-01-01

    The University of Missouri Research Reactor Facility (MURR) located in Columbia, Missouri, is the highest powered, highest steady-state flux university research reactor in the United States. The reactor is a 10-MW pressurized loop, in-pool-type, light-water-moderated, beryllium-reflected, flux trap reactor. MURR has a compact core (0.033 m 3 ) composed of eight fuel elements of the materials test reactor type arranged as an annular right circular cylinder between the inner and outer aluminum pressure vessels. Conservative engineering judgment resulted in the decision in 1988 to purchase new inner and outer pressure vessels. This paper details the difficulties encountered in procuring replacements for aluminum pressure vessels built to standards that are no longer applicable in attempting to meet nuclear standards that are not applicable to nonferrous material

  6. Vessels in Transit - Web Tool

    Data.gov (United States)

    Department of Transportation — A web tool that provides real-time information on vessels transiting the Saint Lawrence Seaway. Visitors may sort by order of turn, vessel name, or last location in...

  7. Underwater Telemetry as a Tool in Aquaculture Research and Development

    Directory of Open Access Journals (Sweden)

    B.A. Holand

    1987-01-01

    Full Text Available Small acoustical transmitters may be used to obtain data from free swimming fish. The main principles behind this technique are described together with some of the equipment developed. Some examples are briefly discussed where heart beats, depth and temperature are measured to describe fish behaviour. Automatic fish tracking equipment that has been used to track fish within an enclosed area is also described.

  8. Reactor vessel sealing plug

    International Nuclear Information System (INIS)

    Dooley, R.A.

    1986-01-01

    An apparatus is described for sealing a cold leg nozzle of a nuclear reactor pressure vessel from a remote location comprising: at least one sealing plug for mechanically sealing the nozzle from the inside of the reactor pressure vessel. The sealing plug includes a plate and a cone assembly having an end part receptive in the nozzle, the plate being axially moveable relative to the cone assembly. The plate and cone assembly have confronting bevelled edges defining an opening therebetween. A primary O-ring is disposed about the opening and is supported on the bevelled edges, the plate being guidably mounted to the cone assembly for movement toward the cone assembly to radially expand the primary O-ring into sealing engagement with the nozzle. A means is included for providing relative movement between the outer plate and the cone assembly

  9. Mobile nuclear reactor containment vessel

    International Nuclear Information System (INIS)

    Thompson, R.E.; Spurrier, F.R.; Jones, A.R.

    1978-01-01

    A containment vessel for use in mobile nuclear reactor installations is described. The containment vessel completely surrounds the entire primary system, and is located as close to the reactor primary system components as is possible in order to minimize weight. In addition to being designed to withstand a specified internal pressure, the containment vessel is also designed to maintain integrity as a containment vessel in case of a possible collision accident

  10. Nuclear reactor vessel inspection apparatus

    International Nuclear Information System (INIS)

    Blackstone, E.G.; Lofy, R.A.; Williams, L.P.

    1979-01-01

    Apparatus for the in situ inspection of a nuclear reactor vessel to detect the location and character of flaws in the walls of the vessel, in the welds joining the various sections of the vessel, in the welds joining attachments such as nozzles, elbows and the like to the reactor vessel and in such attachments wherein an inspection head carrying one or more ultrasonic transducers follows predetermined paths in scanning the various reactor sections, welds and attachments

  11. Reactor vessel stud closure system

    International Nuclear Information System (INIS)

    Spiegelman, S.R.; Salton, R.B.; Beer, R.W.; Malandra, L.J.; Cognevich, M.L.

    1982-01-01

    A quick-acting stud tensioner apparatus for enabling the loosening or tightening of a stud nut on a reactor vessel stud. The apparatus is adapted to engage the vessel stud by closing a gripper around an upper end of the vessel stud when the apparatus is seated on the stud. Upon lifting the apparatus, the gripper releases the vessel stud so that the apparatus can be removed

  12. Reactor Pressure Vessel Steels

    Energy Technology Data Exchange (ETDEWEB)

    Van de Velde, J.; Fabry, A.; Van Walle, E.; Chaoudi, R

    1998-07-01

    SCK-CEN's R and D programme on Reactor Pressure Vessel (RPV) Steels in performed in support of the RVP integrity assessment. Its main objectives are: (1) to develop enhanced surveillance concepts by applying micromechanics and fracture-toughness tests to small specimens, and by performing damage modelling and microstructure characterization; (2) to demonstrate the applied methodology on a broad database; (3) to achieve regulatory acceptance and industrial use. Progress and achievements in 1999 are reported.

  13. Effect of flooding waves on a removal of pollutants from underwater quarries

    Science.gov (United States)

    Lyubimova, Tatyana; Lepikhin, Anatoly; Parshakova, Yanina; Tiunov, Alexey

    2013-04-01

    A characteristic feature of the effects of large-scale sandy gravel extruction from water bodies is the formation of a considerable underwater quarries, that strongly changes the hydrodynamical regimes of these water bodies. Traditionally, to estimate the consequences of the formation of the quarries researchers focus on lowering of the water level at limiting hydrological regimes which have fundamental importance for ensuring the sustainability of the different water intakes. Additionally, the changes in the velocity regimes of water body are estimated from the viewpoint of minimizing the possible erosion processes. There is the Verkhnekamskoye potassium and magnesium salts deposit (the largest in Russia and the second in the world) on Kama river (Kama Reservoir) within Berezniki-Solikamsk-industrial unit. For this deposit the consideration of the formation of quarries is much more complicated because of the presence of significant natural and technogenic output of brines into the Kama reservoir. In this case it is necessary to analyze the problem of estimating the accumulation of the brines in these underwater quarries and to calculate the intensity of the removal of pollutants at their washing due to the changes in the hydrological regime of the water body. The problem of changing the hydrodynamic regime, first of all the lowering of the water level and the calculation of the flow velocity can be solved very successfully in two-and even in one-dimensional approach and the problem of washing the underwater quarries is essentially three-dimensional. In this paper we simulate the removal of contaminants from the underwater quarry. The problem is solved in the framework of unsteady approach. The calculations show that in the flow near the bottom of quarry the vortex is formed whose direction is such that the front edge of the quarry is eroded. The computations and field observations show that, the upper, rather thin (water supply of Kirov city, arises when the

  14. Phenomenological vessel burst investigations

    International Nuclear Information System (INIS)

    Hippelein, K.W.; Julisch, P.; Muz, J.; Schiedermaier, J.

    1985-07-01

    Fourteen burst experiments have been carried out using vessels with circumferential and longitudinal flaws, for investigation of the fracture behaviour, i.e. the time-related fracture opening. The vessels had dimensions (outer diameter x wall thickness = 800 x 47 mm) which correspond to the dimensions of the main coolant piping of a 1300 MW e PWR. The test specimens had been made of the base-safe material 20 MnMoNi 55 and of a special, 22 NiMoCr 37 base alloy. The experimental conditions with regard to pressure and temperature have been chosen so as to correspond to normal operating conditions of a PWR (p∝17.5 MPa, T∝300 0 C), i.e. the flaws have been so dimensioned that failure was to be expected at a pressure of p∝17.5 MPa. As a rule, water has been used as the pressure medium, or in some cases air, in order to influence the time-dependent pressure decrease. Fluid and structural dynamics calculations have also been made. In order to determine the impact of a fast propagating crack on the leak-to-fracture curve, which normally is defined by quasistationary experiments, suitable tests have been made with large-volume, cylindrical vessels (outer diameter x wall thickness x length = 3000 x 21 x 14000 mm) made of the material WSt E 43. The leak-before-fracture criterion has been confirmed. (orig./HP) [de

  15. Blood Vessels in Allotransplantation.

    Science.gov (United States)

    Abrahimi, P; Liu, R; Pober, J S

    2015-07-01

    Human vascularized allografts are perfused through blood vessels composed of cells (endothelium, pericytes, and smooth muscle cells) that remain largely of graft origin and are thus subject to host alloimmune responses. Graft vessels must be healthy to maintain homeostatic functions including control of perfusion, maintenance of permselectivity, prevention of thrombosis, and participation in immune surveillance. Vascular cell injury can cause dysfunction that interferes with these processes. Graft vascular cells can be activated by mediators of innate and adaptive immunity to participate in graft inflammation contributing to both ischemia/reperfusion injury and allograft rejection. Different forms of rejection may affect graft vessels in different ways, ranging from thrombosis and neutrophilic inflammation in hyperacute rejection, to endothelialitis/intimal arteritis and fibrinoid necrosis in acute cell-mediated or antibody-mediated rejection, respectively, and to diffuse luminal stenosis in chronic rejection. While some current therapies targeting the host immune system do affect graft vascular cells, direct targeting of the graft vasculature may create new opportunities for preventing allograft injury and loss. © Copyright 2015 The American Society of Transplantation and the American Society of Transplant Surgeons.

  16. Ionizing radiations and blood vessels

    International Nuclear Information System (INIS)

    Vorob'ev, E.I.; Stepanov, R.P.

    1985-01-01

    Data on phenomenology of radiation-induced changes in blood vessels are systematized and authors' experience is generalized. Modern concepts about processes leading to vessel structure injury after irradiation is critically analyzed. Special attention is paid to reparation and compensation of X-ray vessel injury, consideration of which is not yet sufficiently elucidated in literature

  17. Ionizing radiations and blood vessels

    International Nuclear Information System (INIS)

    Vorob'ev, E.I.; Stepanov, R.P.

    1985-01-01

    Data on phenomeology of radiation changes of blood vessels are systemized and the authors' experience is generalyzed. A critical analysis of modern conceptions on processes resulting in vessel structure damage after irradiation, is given. Special attention is paid to reparation and compensation of radiation injury of vessels

  18. An Underwater Image Enhancement Algorithm for Environment Recognition and Robot Navigation

    Directory of Open Access Journals (Sweden)

    Kun Xie

    2018-03-01

    Full Text Available There are many tasks that require clear and easily recognizable images in the field of underwater robotics and marine science, such as underwater target detection and identification of robot navigation and obstacle avoidance. However, water turbidity makes the underwater image quality too low to recognize. This paper proposes the use of the dark channel prior model for underwater environment recognition, in which underwater reflection models are used to obtain enhanced images. The proposed approach achieves very good performance and multi-scene robustness by combining the dark channel prior model with the underwater diffuse model. The experimental results are given to show the effectiveness of the dark channel prior model in underwater scenarios.

  19. Single underwater image enhancement based on color cast removal and visibility restoration

    Science.gov (United States)

    Li, Chongyi; Guo, Jichang; Wang, Bo; Cong, Runmin; Zhang, Yan; Wang, Jian

    2016-05-01

    Images taken under underwater condition usually have color cast and serious loss of contrast and visibility. Degraded underwater images are inconvenient for observation and analysis. In order to address these problems, an underwater image-enhancement method is proposed. A simple yet effective underwater image color cast removal algorithm is first presented based on the optimization theory. Then, based on the minimum information loss principle and inherent relationship of medium transmission maps of three color channels in an underwater image, an effective visibility restoration algorithm is proposed to recover visibility, contrast, and natural appearance of degraded underwater images. To evaluate the performance of the proposed method, qualitative comparison, quantitative comparison, and color accuracy test are conducted. Experimental results demonstrate that the proposed method can effectively remove color cast, improve contrast and visibility, and recover natural appearance of degraded underwater images. Additionally, the proposed method is comparable to and even better than several state-of-the-art methods.

  20. 3D RECONSTRUCTION OF AN UNDERWATER ARCHAELOGICAL SITE: COMPARISON BETWEEN LOW COST CAMERAS

    Directory of Open Access Journals (Sweden)

    A. Capra

    2015-04-01

    Full Text Available The 3D reconstruction with a metric content of a submerged area, where objects and structures of archaeological interest are found, could play an important role in the research and study activities and even in the digitization of the cultural heritage. The reconstruction of 3D object, of interest for archaeologists, constitutes a starting point in the classification and description of object in digital format and for successive fruition by user after delivering through several media. The starting point is a metric evaluation of the site obtained with photogrammetric surveying and appropriate 3D restitution. The authors have been applying the underwater photogrammetric technique since several years using underwater digital cameras and, in this paper, digital low cost cameras (off-the-shelf. Results of tests made on submerged objects with three cameras are presented: © Canon Power Shot G12, © Intova Sport HD e © GoPro HERO 2. The experimentation had the goal to evaluate the precision in self-calibration procedures, essential for multimedia underwater photogrammetry, and to analyze the quality of 3D restitution. Precisions obtained in the calibration and orientation procedures was assessed by using three cameras, and an homogeneous set control points. Data were processed with © Agisoft Photoscan. Successively, 3D models were created and the comparison of the models derived from the use of different cameras was performed. Different potentialities of the used cameras are reported in the discussion section. The 3D restitution of objects and structures was integrated with sea bottom floor morphology in order to achieve a comprehensive description of the site. A possible methodology of survey and representation of submerged objects is therefore illustrated, considering an automatic and a semi-automatic approach.